<DOC>
[109 Senate Hearings]
[From the U.S. Government Printing Office via GPO Access]
[DOCID: f:25119.wais]
S. Hrg. 109-249
STEM CELLS RESEARCH, 2005
=======================================================================
HEARING
before a
SUBCOMMITTEE OF THE
COMMITTEE ON APPROPRIATIONS UNITED STATES SENATE
ONE HUNDRED NINTH CONGRESS
FIRST SESSION
__________
SPECIAL HEARING
OCTOBER 19, 2005--WASHINGTON, DC
__________
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__________
COMMITTEE ON APPROPRIATIONS
THAD COCHRAN, Mississippi, Chairman
TED STEVENS, Alaska ROBERT C. BYRD, West Virginia
ARLEN SPECTER, Pennsylvania DANIEL K. INOUYE, Hawaii
PETE V. DOMENICI, New Mexico PATRICK J. LEAHY, Vermont
CHRISTOPHER S. BOND, Missouri TOM HARKIN, Iowa
MITCH McCONNELL, Kentucky BARBARA A. MIKULSKI, Maryland
CONRAD BURNS, Montana HARRY REID, Nevada
RICHARD C. SHELBY, Alabama HERB KOHL, Wisconsin
JUDD GREGG, New Hampshire PATTY MURRAY, Washington
ROBERT F. BENNETT, Utah BYRON L. DORGAN, North Dakota
LARRY CRAIG, Idaho DIANNE FEINSTEIN, California
KAY BAILEY HUTCHISON, Texas RICHARD J. DURBIN, Illinois
MIKE DeWINE, Ohio TIM JOHNSON, South Dakota
SAM BROWNBACK, Kansas MARY L. LANDRIEU, Louisiana
WAYNE ALLARD, Colorado
J. Keith Kennedy, Staff Director
Terrence E. Sauvain, Minority Staff Director
------
Subcommittee on Departments of Labor, Health and Human Services, and
Education, and Related Agencies
ARLEN SPECTER, Pennsylvania, Chairman
THAD COCHRAN, Mississippi TOM HARKIN, Iowa
JUDD GREGG, New Hampshire DANIEL K. INOUYE, Hawaii
LARRY CRAIG, Idaho HARRY REID, Nevada
KAY BAILEY HUTCHISON, Texas HERB KOHL, Wisconsin
TED STEVENS, Alaska PATTY MURRAY, Washington
MIKE DeWINE, Ohio MARY L. LANDRIEU, Louisiana
RICHARD C. SHELBY, Alabama RICHARD J. DURBIN, Illinois
ROBERT C. BYRD, West Virginia (Ex
officio)
Professional Staff
Bettilou Taylor
Jim Sourwine
Mark Laisch
Sudip Shrikant Parikh
Candice Rogers
Lisa Bernhardt
Rachel Jones
Ellen Murray (Minority)
Erik Fatemi (Minority)
Adrienne Hallett (Minority)
C O N T E N T S
----------
Page
Opening statement of Senator Arlen Specter....................... 1
Statement of Senator Mary L. Landrieu............................ 2
Prepared statement........................................... 2
Statement of Senator Tom Harkin.................................. 4
Statement of Senator Thad Cochran................................ 4
Statement of Anthony Herrera, author and cancer survivor......... 5
Prepared statement........................................... 7
Statement of Judith Gasson, Ph.D., director, Jonsson
Comprehensive Cancer Center.................................... 8
Prepared statement........................................... 9
Statement of Rudolf Jaenisch, M.D., professor of biology,
Massachusetts Institute of Technology.......................... 10
Prepared statement........................................... 12
Statement of Steven Teitelbaum, M.D., Wilma and Roswell Messing,
professor of Pathology and Immunology, Washington University
School of Medicine............................................. 14
Prepared statement........................................... 16
Statement of John Wagner, M.D., scientific director of clinical
research, Blood and Marrow Transplant Program and Stem Cell
Institute...................................................... 17
Prepared statement........................................... 19
STEM CELLS RESEARCH, 2005
----------
WEDNESDAY, OCTOBER 19, 2005
U.S. Senate,
Subcommittee on Labor, Health and Human
Services, Education, and Related Agencies,
Committee on Appropriations,
Washington, DC.
The subcommittee met at 9:31 a.m., in room SD-138, Dirksen
Senate Office Building, Hon. Arlen Specter (chairman)
presiding.
Present: Senators Specter, Cochran, Harkin, and Landrieu.
OPENING STATEMENT OF SENATOR ARLEN SPECTER
Senator Specter. Good morning.
Today our focus is on stem cells. Our hearing coincides
with the announcement by the South Korean Nuclear
Transplantation Consortium that they are starting an operation
today on a world stem cell foundation which will be based in
the Seoul National University in South Korea with satellite
offices in San Francisco and England. I applaud what they are
doing, but I regret that the United States is falling farther
behind in world leadership on scientific research generally and
specifically on stem cell research.
Now, this is the 17th hearing which this subcommittee has
held on this important subject since we first learned about
stem cells in November 1998. It is well known that the stem
cells have the possibility for curing or alleviating the
problems of so many maladies.
The House of Representatives has passed legislation which
would remove the restriction by the Federal Government on
funding stem cell research, and Senator Harkin and I have
introduced identical legislation in the Senate, S. 471. The
House bill received support from some 50 Republicans crossing
party lines, and it is my view that with sufficient focus and
sufficient attention, there could be amassed enough votes to
override a presidential veto. I say that regretfully and
reluctantly, but this is a matter of utmost importance and has
a direct impact to some 110 million Americans.
President Nixon declared war on cancer in 1970 and had the
United States devoted the resources to that war which we devote
to other wars, I think the war on cancer could have been won. I
say that with special concern because I have had my own
problems with Hodgkin's lymphoma cancer this year, and cancer
continues to claim deaths in the hundreds of thousands.
This happens to be an especially busy day. Most days are
busy on Capitol Hill, but we are in the midst of proceedings on
the nomination of Ms. Miers for the Supreme Court, and I am
going to have to excuse myself at about 10:00, but I will have
an opportunity before that occurs to hear all of the witnesses.
Now I would like to yield to my distinguished ranking
member, Senator Harkin.
Senator Harkin. Thank you very much, Mr. Chairman. Senator
Landrieu I know has to leave right away. If I could just yield
a couple minutes for her of my time, I would appreciate it.
Senator Specter. Well, I was about to yield a couple
minutes to Senator Cochran, but since you spoke first, Senator
Landrieu.
STATEMENT OF SENATOR MARY L. LANDRIEU
Senator Landrieu. Thank you, Mr. Chairman. I thank Senator
Harkin just for one moment because I have got to leave for
another meeting. It is a very busy day, as the chairman said.
Let me thank the chairman and Senator Harkin for their
pursuit of a solution to this dilemma and to this great
challenge. I have a slightly different view that I will submit
for the record in written testimony.
For this morning, I will just say that as we pursue cures
for the many diseases that challenge us and while I understand
that embryonic stem cells hold promise for curing diseases, as
the chairman and many others have pointed out, I think that we
have to be very mindful of what many of our ethical leaders
have said and the Catholic bishops in particular that it is
important in the pursuit of progress to not undermine human
dignity. And there is a line that can be drawn between progress
and human dignity, and creating embryonic stem cells for the
purpose of creating human beings for the purposes of destroying
them for science crosses that line in my opinion.
PREPARED STATEMENT
I will submit more to the record, but I understand that
this will be a continued debate, and I thank the Senator for
allowing me to express my views.
Senator Specter. Thank you, Senator Landrieu.
[The statement follows:]
Prepared Statement of Senator Mary L. Landrieu
Thank you, Mr. Chairman. I have had the privilege of serving as a
member of this subcommittee for four years now. I think it is important
to note that one of the very first hearings I attended was on this very
issue. A lot has changed since then--both in the ethical debate and in
the science. But what have not changed are the moral parameters that
must guide us in these decisions. As Richard Doerflinger of the
Catholic Conference of Bishops put it--``We must be careful not to
undermine human dignity in the pursuit of human progress.''
Since that hearing four years ago, in August of 2001, the President
issued an executive order, allowing for federal funding for stem cell
research on the then existing stem cell lines. In November of that same
year, he appointed a council to monitor stem cell research, to
recommend appropriate guidelines and regulations, and to consider all
of the medical and ethical ramifications of biomedical innovation. To
date, this council has issued six hundred plus page reports on the
bioethics issues involved in stem cell research. Meanwhile, the
scientific community has moved forward in its advancements in knowledge
and discovery. And everyday we, as members of Congress are faced with
the questions of how far we should go in the name of science.
There is no doubt that embryonic stem cell research holds the
promise of curing diseases such as Parkinson's, diabetes, Alzheimer's
and cancer. Even President Bush stressed the importance of federally
funded research in approving the original stem cell lines in 2001--he
explicitly stated that federal dollars help attract the best and
brightest scientists and help ensure that new discoveries are widely
shared at the largest number of research facilities. Federal funding
not only allows us to encourage and financially support this research,
it allows us to use the power of the purse to be sure it is done in the
most safe and ethical way possible. Mr. Chairman, I want to state
clearly for the record, I support federal funding for embryonic stem
cell research provided that the embryos used in these studies are those
that are in excess from the fertility process and are knowingly donated
for this purpose.
I have met with many constituents suffering from life altering and
fatal diseases and they have told me the impact that this research may
have on their lives. One such constituent who I will never forget is a
nine year old girl, Sarah, who suffers from juvenile diabetes. Sarah
told me of her daily routine of shots and blood tests. Her parents told
me of some of the effects of diabetes such as vision loss, kidney
failure, blindness, nerve damage, amputations, heart attack, and
stroke. They begged me, on her behalf, not to block this important
research that could mean a normal childhood for Sarah. Sarah is not
alone in this hope, 35 children a day are diagnosed with Type One
Diabetes.
There are currently 400,000 frozen embryos at IVF clinics around
the country--88.2 percent of which are used for implantation in the
mother's womb--2.8 percent are given up for adoption--the wonderful
``snowflake babies'' we all hear so much about. This translates to a
total of 11,000 embryos that are not going to be implanted and are
voluntarily donated. It is important to note, if these embryos were not
donated then they would be destroyed--not for science--but thrown away
with the rest of the medical waste for the day. We cannot allow these
valuable embryos to be discarded when even according to the President's
Council on Bioethics, ``stem cells and their derivatives may prove a
valuable source of transplantable cells and tissues for repair and
regeneration. If these healing powers could be harnessed, the medical
benefits for humankind would be immense, perhaps ushering in an era of
truly regenerative medicine.''
Please do no let my views expressed today confuse your
understanding of my support of legislation banning human cloning.
Embryonic stem cell research using excess embryos from IVF treatments
and creating cloned embryos for scientific purposes should not be
confused. I believe that creating a human embryo for the sole purpose
of its destruction through experimentation is wrong, unethical and
should be illegal. Since I mentioned the hearing on stem cell research
conducted by this committee four years ago at the beginning of my
remarks, I think it is important to note that many members of this
subcommittee also expressed concerns about the creation of human
embryos for research.
The human body is not a product to be mass-produced and stripped
for parts, most especially in the earliest stages of its development--
women's eggs and wombs should never be commodities sold to the highest
bidders. But this is a very real risk of so called ``therapeutic
cloning.'' Experts estimate that over 800 million eggs would be needed
to support one-sixteenth of the possible human cloning experiments. We
are already getting reports that clinical researchers in Seoul, Korea,
in England, and in San Francisco will be working with the South Korean
veterinarian and stem-cell biologist whose laboratory leads the world
in the use of the somatic-cell nuclear transfer technique, to recruit
women to donate eggs and patients to donate somatic cells.
What's more, regardless of what proponents of this research will
tell you, there is only one kind of cloning. The only difference
between what has come to be called ``reproductive cloning'' and
``therapeutic cloning'' is what is done with the clones once they are
created. Legislation that purports to ban the birth of a cloned human
being does not ban its creation, only its implantation into a human
uterus. Once we support and encourage the creation of millions of
cloned human beings, do we really believe we would have the power to
successfully monitor and ban their implantation? The only effective way
to ban human cloning is to stop the process before it starts.
Finally, Mr. Chairman, it is because I believe that there is
immense potential in embryonic and adult stem cell research that I
oppose federal support for human cloning. I believe that banning, even
if only temporarily, this one procedure helps to focus science and
funding for research to equally promising but less problematic areas
such as embryonic and adult stem cell research.
I look forward to hearing from the witnesses today and thank you,
Chairman Specter for holding this important hearing.
Senator Specter. Senator Harkin.
STATEMENT OF SENATOR TOM HARKIN
Senator Harkin. Thank you, Mr. Chairman. Again, let me just
compliment you on your great leadership on a lot of things, but
especially on this issue since 1998, as you mentioned, and for
calling this hearing.
We have had a pretty busy year with hurricanes on the Gulf
Coast, of course, and as the chairman knows better than anyone
else, the Senate having to have hearings on two Supreme Court
nominees, which the chairman chairs that committee. And yet,
the need to continue our push for stem cell research is as
critical as ever.
I was privileged this summer to meet with some of the South
Koreans, and you mentioned the article that was in the paper
this morning, Mr. Chairman, that they are moving ahead on this,
the whole area of somatic cell nuclear transfer, and the kind
of promise that holds.
I am just hopeful that we can move ahead on this. People
are suffering and dying. They need hope. We know this holds
great promise. We all know that medical research is not just
done by one person, not done by two. The best research is when
a lot of people are involved in it and it is spread around.
That is what we need to do. We need to get more involved in
this type of research.
Yet, we have manacles put on our researchers today and we
need to remove those. That is what the bill that Senator
Specter and I have supported, the one that passed the House,
does. That is why we hope today we can move ahead with a look
at somatic cell nuclear transfer and what that means for the
future of stem cell research.
So, again, Mr. Chairman, I thank you for holding this
hearing and, again, I thank you for your great leadership on
this issue.
Senator Specter. Senator Cochran, would you care to make an
opening statement?
STATEMENT OF SENATOR THAD COCHRAN
Senator Cochran. Mr. Chairman, thank you very much. I
congratulate you on your continued strong leadership in helping
to explore the possibilities that medical research holds for
curing and preventing illness and disease. You have done more
than anybody I can remember since I have been in the Senate to
not only focus attention on these opportunities that we have to
legislate and support research and to authorize programs to
achieve these goals. So I congratulate you and thank you again
for this hearing.
I am really here to introduce Anthony Herrera who is a
friend of mine since 1961, who is a member of this panel. So I
will await your advice as to when that would be appropriate.
Senator Specter. Well, thank you very much, Senator
Cochran. We appreciate your continuing support for this
subcommittee and your membership on the subcommittee,
notwithstanding your very onerous duties as chairman of the
full Appropriations Committee.
STATEMENT OF ANTHONY HERRERA, AUTHOR AND CANCER
SURVIVOR
Senator Specter. We now move to our panel of witnesses and
our lead witness is Mr. Anthony Herrera. I yield to you again,
Mr. Chairman, for the formal introduction.
Senator Cochran. Thank you very much. It is a great
pleasure for me to introduce to the committee Anthony Herrera,
whom I have known since 1961. We met when I was entering my
first year of law school and he was beginning his first year of
undergraduate school at the University of Mississippi, and I
happened to be in the same residence hall and became the
dormitory manager, as we called it, back in those days. He was
young, but energetic, full of an interest in all of the things
that were going on at that campus.
He became an excellent student and then went on to a
successful career in the performing arts as an actor, writer,
director. He has been on As the World Turns off and on for a
long, long time. James Stenbeck is his stage name on that show.
And James Stenbeck has been a survivor too of sorts. He would
disappear. People would think he was a goner and then he would
reappear sometime later full of life and enthusiasm. That is
the story of Anthony Herrera as well.
He has battled cancer and has survived. He has written a
book about it, The Cancer War, which I recommend. I know the
chairman has read it. I have read it. It is very instructive
into the challenges that confront someone who is a victim of
lymphoma or other forms of cancer. He had a rare kind of
lymphoma. And transplants of bone marrow, stem cells, all of
these things have been involved in his life. He has lived
through it all and can help us understand the challenges that
victims face and the possible successes there are in our effort
to deal more successfully with some of these forms of cancer.
So it is a great pleasure for me to welcome him and thank
him for being here to help us understand the challenges.
Senator Specter. Thank you very much, Mr. Chairman.
Mr. Herrera, we do very much appreciate your being here
today, especially since you came from Buenos Aires to
participate in this hearing. I compliment you on the book which
you have written, and I pay particular note to your references
to stem cells as they relate to your situation.
We now begin the customary 5-minute rounds for the
witnesses and we start with Mr. Anthony Herrera.
Mr. Herrera. Thank you.
In January 1997 at New York Hospital, I was diagnosed with
mantle cell lymphoma and was told this disease will kill you.
There is nothing we can do. You are going to die.
Then without anesthesia, this oncologist drilled through my
skin, through my periosteum and into the bone, and extracted
marrow. The pain was incredible.
That night I debated whether to put my .38 Smith & Wesson
to my temple and pull the trigger or saddle up. I pondered each
option. Then I pictured myself on a horse riding into a dark
canyon. I found a poem by Tennessee Williams from the Night of
the Iguana. I read it every day.
I then went to Sloan Kettering where I was told we are
going to work hard and hope for the best. They had a new
protocol for mantle cell developed with a hospital in Paris. I
was the fifth patient in the United States to undergo this
regimen, massive amounts of chemotherapy and total body
irradiation to kill lymphoma cells and take my immune system to
zero.
On August 1, 1997, I received an autologous stem cell
transplant, autologous meaning the stem cells were taken from
my body. My mouth was full of sores. My skin was gray. I had no
hair, no fingernails, no toenails, but I was found to be in
remission. I lived under the belief that if the disease came
back that I would die.
In November 1998, I relapsed but during these 18 months, a
new approach to the stem cell transplant for mantle cell had
been developed at M.D. Anderson Cancer Center in Houston, Texas
where I was admitted March 30, 1999.
In April, I underwent an allogeneic stem cell transplant
using a non-myeloablative regimen, allogeneic meaning the cells
came from a donor, non-myeloablative meaning they did not burn
my immune system to zero with chemo, hence less toxicity.
Six weeks later, the lymphoma was still active. We tried a
donor lymphocyte infusion, adding more of my brother's cells. I
then suffered from CMV. I bled internally and lost 30 pounds in
3 weeks, followed by a mild stroke and a seizure, but I was in
remission.
One year later, August 15, 2000, the CT-scan showed that I
had relapsed. The disease was back. I was told without
treatment you will die in less than 12 months and that another
donor lymphocyte infusion could kill you. There was a small
amount of disease, so I had time to think.
Six weeks later, I saddled up and requested a CT-scan. At
this juncture, medical history was made. This scan showed less
disease than 6 weeks before, which meant that my new immune
system had started fighting the lymphoma without chemotherapy,
without drugs, without radiation. My new immune system was
taking out the cancer, my new immune system and my bone marrow
created by donor stem cells.
Throughout this journey, I listened to Willie Nelson, Louis
Armstrong, and Agustin Lara of Mexico. I recited Tennessee
Williams every day. I quoted from John Ford's The Searchers.
When asked if he wanted to quit, John Wayne retorted, that will
be the day.
I found dedicated and inspired doctors and nurses, such as
Sergio Giralt and Joyce Newman, doctors and nurses with guts
and vision.
In 1950, William Faulkner won the Nobel Peace Prize for
literature. He concluded his acceptance speech with the
following. ``I believe that man will not merely endure: he will
prevail. He is immortal, not because he alone among creatures
has an inexhaustible voice, but because he has a soul, a spirit
capable of compassion and sacrifice.
``The writer's duty is to write about these things. It is
his privilege to help man endure by lifting his heart, by
reminding him of the courage and honor and hope and pride and
compassion and pity and sacrifice which have been the glory of
his past. The poet's voice need not merely be the record of
man, it can be one of the props, the pillars to help him endure
and prevail.''
I hope that you Senators and this Congress find it is your
privilege and your duty to fight with your intelligence and
pride and compassion to continue to build the pillars of man,
the arts for the spirit, education for the mind, and medical
research for the body.
PREPARED STATEMENT
Ladies and gentlemen, let me leave you with this thought.
The stem cell is the future of medicine and I am alive because
of the progress in stem cell research. Thank you.
[The statement follows:]
Prepared Statement of Anthony Herrera
I was diagnosed with Mantle Cell Lymphoma in January of 1997 and
was told at New York University Hospital, ``This disease will kill you.
There is nothing we can do. You are going to die.''
That night I debated whether to put my .38 Smith & Wesson to my
temple and pull the trigger or ``saddle up.'' I pondered each option.
Then I saw myself on HORSE heading into a dark canyon.
I found a poem by Tennessee Williams from the Night of the Iguana.
I read it every day.
I then went to Memorial Sloan-Kettering and was treated with a
regimen of chop and ICE chemotherapy and total body irradiation.
On August 1, 1997 I received an autologous stem cell transplant and
was found to be in remission.
In November 1998, I relapsed and received four cycles of
chemotherapy. On March 30, 1999 I was admitted to the University of
Texas, M.D. Anderson Cancer Center in Houston Texas, under the care of
Dr. Issa Khouri, M.D.
I underwent an allogeneic stem cell transplantation using a non-
myeloablative regimen. My brother John, was my donor. I required a
boost of donor lymphocyte infusion after transplantation.
I then suffered from CMV, a mild stroke and a seizure.
I was found to be in remission August 15, 1999.
This treatment was based on a concept developed at M.D. Anderson
Cancer Center, that many neoplastic diseases can be treated by immune
modulation only without the need for toxic high dose chemotherapy.
Up until recently high dose chemotherapy was considered essential
for marrow or stem cell transplantation.
This new treatment offers new hope and new horizons for patients
suffering from this otherwise fatal disease.
I relapsed August 15, 2000. I was told without treatment ``You will
die in less than twelve months.'' And that ``another donor lymphocyte
infusion--could kill you.''
He then worked with Dr. Ira Braunschweig, formerly of MD Anderson
Cancer Center, now medical director of Director of Bone Marrow
Transplantation--The Albert Einstein College of Medicine. The plan at
that time was to use Rituxan to control the lymphoma and then return to
MD Anderson for a donor lymphocyte infusion.
A CAT-scan from September 27, 2000 showed less disease without any
treatment of any kind. This meant that his new immune system had
started battling the disease.
This was a medical history in the treatment of Mantle Cell Lymphoma
in that the new immune system had started killing lymphoma cells and
there by reducing the amount of disease without treatment of any kind.
Dr. Braunschweig and I debated and then decided to proceed with
four rounds of high dose Rituxan during the month of October, with the
hope that the Rituxan would assist his new immune system in the battle.
CAT scans and Gallium scans that followed from November through 30
January 2001 showed a steady decrease in the amount of lymphoma and
lymphoma related activity.
Dr. Braunschweig and I have discussed several times whether there
was a chance the rituxan aided his new immune system in the battle to
control the Mantle Cell Lymphoma.
We will never know.
What is concluded by Dr. Braunschweig, Dr. Andre Goy, Dr. James
Gajewski and Dr. Sergio Giralt is that the donor infusion of my
brother's cells and the engrafting of this new immune system in his
body that has kept me in remission for five years.
This unexpected development of Graft vs. Lymphoma approach is
positive news for fighting cancer and other life threatening diseases.
Throughout this journey I listen to Willie Nelson, Louis Armstrong
and Agustin Lara of Mexico. I quoted Tennessee Williams every day. I
quoted from John Ford's THE SEARCHERS . . . When was asked if he wanted
to quit. John Wayne retorted, ``That'll be the day.''
I am alive because of great Doctors and nurses with guts and
vision. 1950 William Faulkner won the Nobel Prize for Literature . . .
he concluded his speech with the following.
I believe that man will not merely endure: he will prevail. He is
immortal, not because he alone among creatures has an inexhaustible
voice, but because he has a soul, a spirit capable of compassion and
sacrifice and endurance.
The poet's, the writer's, duty is to write about these things. It
is his privilege to help man endure by lifting his heart, by reminding
him of the courage and honor and hope and pride and compassion and pity
and sacrifice which have been the glory of his past. The poet's voice
need not merely be the record of man, it can be one of the props, the
pillars to help him endure and prevail . . .
The stem cell is the future of medicine . . .
I hope you senators and this congress find that it is your
privilege and duty to fight with your intelligence and pride and
compassion to continue to build the pillars of man--the arts for the
spirit--education for the mind and medical research for the body. Stem
cell research. All stem cell research.
Thank you.
Senator Specter. Thank you very much, Mr. Herrera, for that
very poignant and emphatic testimony and for the authentication
as to what stem cells can do, for what they have done for you.
Our next witness is Dr. Judith Gasson, Director of Jonsson
Comprehensive Cancer Center at UCLA. Dr. Gasson has a doctorate
in physiology from the University of Colorado and post-doctoral
work at Saulk Institute. Thank you very much for joining us
today, Dr. Gasson, and the floor is yours.
STATEMENT OF JUDITH GASSON, Ph.D., DIRECTOR, JONSSON
COMPREHENSIVE CANCER CENTER
Dr. Gasson. Thank you very much, Mr. Chairman. It is a
great pleasure to continue the conversation that you and I
began several years ago when you were visiting UCLA Medical
School. At that time, we had a very serious discussion about
how important it was that we continue to do this very important
stem cell work, and I am happy to be here today.
Cancer is now the leading cause of death in Americans under
the age of 85. This year alone, 550,000 Americans will die from
their disease. These numbers fail to account for the additional
pain and suffering felt by their families and friends.
Many scientists believe that stem cell research has the
power to revolutionize cancer therapy in much the same way that
targeted therapies have impacted cancer treatment over the past
decade. There is now considerable evidence that many types of
cancer, including breast cancer, prostate, brain, and certain
leukemias, arise through mutations that occur in our adult stem
cells. These so-called cancer stem cells retain the ability to
self-renew, which is a signature feature of stem cells.
However, they lose the ability to respond to the proper cues
and to differentiate.
Our current therapies are targeted to the bulk of the tumor
and not to the cancer stem cell. How can we develop therapies
that destroy the malignant stem cells, thereby eliminating both
the tumor and its chance to recur at a later time? Like all
therapeutic advances, targeting cancer stem cells must be based
on outstanding basic science. For this reason, embryonic stem
cells must be studied to educate us on the fundamental
processes and pathways that drive the growth of cancer stem
cells.
To be sure, studies are ongoing on adult stem cells, but
these studies are incomplete and unable to answer all of the
critical questions. Adult stem cells are rare in our bodies and
cannot be induced to grow in the laboratory without also
differentiating.
We believe that characterizing the pathways that embryonic
stem cells use to self-renew, using high-throughput screening
technology, will allow us to develop small molecule inhibitors
to those stem cell-specific pathways. If these chemical
inhibitors of self-renewal of embryonic stem cells are isolated
and characterized in the laboratory, they may actually provide
the first benefit of stem cell research in patients.
Paradoxically, as you just heard from Mr. Herrera, bone
marrow stem cells are not only perhaps the source of some
cancers, but they also have been used to treat certain cancers
for the past 4 decades. Many patients are unable to benefit
from this potentially life-saving treatment because they either
do not have a matched bone marrow donor or their own bone
marrow has been compromised by treatment or invasion of cancer
cells. The technique of somatic cell nuclear transfer would
enable us to insert the DNA from a cancer patient's skin cells
into an egg and reprogram that DNA to become a pluripotent stem
cell again. In this way, the patient's blood and immune systems
could be reconstituted and genetically identical to the
patient.
It has been estimated that there are currently 400,000
frozen embryos generated in in vitro fertilization clinics that
will not be used. The vast majority of these frozen cells will
be destroyed.
The thousands of physicians and scientists, represented by
the American Association of Cancer Research and the American
Society of Clinical Oncology, issued public statements this
year strongly endorsing the expansion of funding for embryonic
stem cell research to improve the prevention, detection, and
treatment of cancer. We estimate that this represents 30,000
physicians and scientists who believe that this important work
will have an impact on the dreaded disease of cancer.
PREPARED STATEMENT
To be sure, my commitment to this area of research is
professional, but it is also personal. Three years ago next
week I lost my own father to lymphoma.
Thank you very much, Mr. Chairman.
[The statement follows:]
Prepared Statement of Judith Gasson
Cancer is now the leading cause of death in Americans under the age
of 75. This year alone 550,000 Americans will die from their disease.
These numbers fail to account for the additional pain and suffering
felt by their family and friends.
Many scientists believe that stem cell research has the power to
revolutionize cancer therapy in much the same way that ``targeted''
therapies have impacted cancer treatment over the past decade. There is
now considerable evidence that many types of cancer including breast,
prostate, brain and leukemias arise through mutations acquired in our
adult stem cells. These so-called ``cancer stem cells'' retain the
ability to self-renew, which is the signature feature of stem cells.
However they lose the ability to respond to normal differentiation
signals.
Our current therapies are targeted to the bulk of the tumor, but
not to the cancer stem cells. How can we develop therapies that destroy
the cancer stem cells, thereby eliminating the tumor and its chances to
recur? Like all therapeutic advances targeting cancer stem cells must
be based upon outstanding basic science. For this reason embryonic stem
cells must be studied to educate us on the fundamental processes and
pathways that drive the growth of cancer stem cells. To be sure studies
are ongoing with adult stem cells, but these studies are incomplete and
unable to answer all of the critical questions. Adult stem cells are
rare and cannot be induced to grow in the laboratory without also
differentiating. We believe that characterizing the pathways that
embryonic stem cells use to self-renew, using high-throughput screens,
will lead to the development of small molecule inhibitors. It is these
chemical inhibitors of self-renewal of embryonic stem cells that may
provide the first benefits of stem cell research in patients.
Paradoxically bone marrow stem cells have been used to treat
certain cancers for the past four decades. Many patients are unable to
benefit from this potentially life-saving treatment because they don't
have a matched bone marrow donor and their own bone marrow has been
comprised by treatment or invaded by cancer cells. The technique of
somatic cell nuclear transfer would enable us to insert DNA from a
cancer patient's skin cell into an egg and re-program it from a skin
cell to a pluripotent stem cell. In this way, the patient's blood and
immune systems could be reconstituted and genetically identical to the
patient.
It's been estimated that there are currently 400,000 frozen embryos
generated from in vitro fertilization that will not be used. The vast
majority of these will be destroyed. The thousands of physicians and
scientists represented by the American Association of Cancer Research
and the American Society of Clinical Oncology issued public statements
this year strongly endorsing the expansion of funding for embryonic
stem cell research to improve the prevention, detection and treatment
of cancer.
Senator Specter. Thank you very much, Dr. Gasson.
Our next witness is Dr. Rudolf Jaenisch, Professor of
Biology at Massachusetts Institute of Technology and a member
of the Whitehead Institute for Biomedical Research. He received
his doctorate in medicine from the University of Munich. Thank
you for joining us today, Dr. Jaenisch, and we look forward to
your testimony.
STATEMENT OF RUDOLF JAENISCH, M.D., PROFESSOR OF
BIOLOGY, MASSACHUSETTS INSTITUTE OF
TECHNOLOGY
Dr. Jaenisch. Thank you, Mr. Chairman.
So I am a founding member of the Whitehead Institute and a
professor of biology at MIT. My main research interest is
epigenetic regulation, embryonic stem cells, and to understand
the mechanisms of nuclear transfer and the reprogramming of the
genome following nuclear transfer. We have studied this in
mice, and the conclusion from all work was that reproductive
cloning in humans is unsafe and should be banned.
Our work was also of relevance for the therapeutic
application of somatic cell nuclear transfer. We have done this
in a mouse model again of severe combined immune deficiency,
SCID. This condition exists in humans. And we have used this
technique to restore the immune system in these mice. And I
believe that this proof of principle experiment is directly
relevant for treatment of human blood diseases, such as
leukemia as we heard.
The recent success by the Korean group indicates that
nuclear transfer in humans is much more efficient than we
assumed before, and they believe the treatment of bone marrow
diseases will likely be the first human disease that will be
treated by SCNT.
Embryonic stem cells clearly--and we heard this--are of
great potential value to treat diseases, and I am confident
that if we are allowed to derive new stem cells from in vitro
fertilized embryos, that would enormously help us to understand
the system. But I want to talk about nuclear transfer today.
The proof of principle experiments are clear. In principle,
this technology will work in humans to treat diseases such as
blood diseases, Parkinson's, and diabetes. We have to learn
technology, but this I think is only technology.
So what are the concerns of those who oppose nuclear
cloning in humans for the purpose of generating customized
embryonic stem cells for therapy or for research?
I believe the key concern is that the derivation of an
embryonic stem cell from a cloned construct would necessarily
involve the destruction of the blastocyst and thus destruction
of potential normal human life. The crucial question is: does
the cloned blastocyst really represent potential normal human
life? And that is what I want to concentrate on.
From all experience with cloned animals, I would argue that
the cloned blastocyst has little, if any, potential to ever
develop into a normal baby. Most will die in development and
the few that survive to birth will develop severe defects with
age because of the reprogramming faults following nuclear
transplantation.
For these reasons, it has been suggested, because a cloned
blastocyst is so different from the normal blastocyst which is
derived from a fertilized egg, that it should not be designated
as an embryo. And I agree with this notion. However, we have to
admit that the cloned blastocyst has a chance, although an
exceedingly small chance, to develop into cloned animals such
as Dolly. But Dolly died because she suffered from major
ailments, as most clones do. But it is this statistically small
chance of a clone to develop to birth and beyond what troubles
most who oppose the technology.
The altered nuclear transfer approach has been proposed by
Dr. Hurlbut as a potential solution. This approach would cause
the product of nuclear transfer to be inherently unable to ever
develop into a fetus or a baby because of its inability to
establish the very first step of embryonic organization and the
inability to establish that fetal/maternal connection. The
procedure, as proposed by Hurlbut, involves the genetic
manipulation of the donor cell, not of the embryo, with the
goal to generate a construct which can still generate embryonic
stem cells but cannot implant and generate a fetus. So the goal
is, therefore, to generate what he calls a biological construct
or biological artifact that lacks the essential attributes of
an embryo and has no potential whatsoever to develop into a
fetus but still could proliferate and give rise to ES cells.
ANT, altered nuclear transfer, was last year proposed as a
thought experiment. We have now performed the proof of
principle experiment in the mouse, published this week in
Nature, that validates this proposal. So let me explain.
In our experiment, we introduced an RNAi construct into the
skin cells prior to nuclear transfer. The RNAi was directed
against Cdx2. This is a gene which is crucial for the
establishment of the very first lineage in embryonic
development which is established at the 16-cell stage. The
genetically altered skin cells do not express Cdx2, but once
the nucleus is transferred to the egg, the cloned product
cannot establish this key lineage. It will develop still to an
abnormal blastocyst which collapses because the trophectoderm
lineage, which will give rise to the placenta, cannot form.
The embryonic stem cells derived from this construct are
indistinguishable in their potential from a normal embryonic
stem cell. So the key question for the debate here is: does it
generate embryos and how abnormal are they?
So I would argue that the ANT, altered nuclear transfer,
embryo is already abnormal at the 4- to 8-cell stage
molecularly because the gene is then expressed. It is not
expressed then. But it becomes morphologically only abnormal
within 2 cell divisions.
Senator Specter. Dr. Jaenisch, could you summarize your
testimony at this point? Your full statement will be made a
part of the record.
Dr. Jaenisch. So I will then summarize that the question is
can we designate these ANT embryos as normal, these ANT
blastocysts as normal embryos. And I would think they are a
mass of differentiating cells, but they definitely lack the
intricate organization of the embryo and its potential.
PREPARED STATEMENT
I want to emphasize that ANT is a modification, not an
alternative, to nuclear transplantation. It requires additional
manipulation of the donor cells that may complicate the
logistics of an already complex procedure, and this has
concerned many scientists. However, our procedure has shown
that the procedure is so simple and straightforward that it may
be acceptable as a requirement if it would resolve the ethical
objections against somatic cell nuclear transfer and allow this
research to go ahead.
[The statement follows:]
Prepared Statement of Dr. Rudolf Jaenisch
Mr. Chairman and members of the Subcommittee, my name is Rudolf
Jaenisch. I am a founding Member of the Whitehead Institute and
Professor of Biology at MIT. Before coming to the Whitehead Institute I
was the head of the Department of Tumor Virology at the Heinrich-Pette
Institute of the University of Hamburg in Germany. I am privileged to
have helped establish the field of transgenic science. Transgenic
science deals with the transfer of genes to create mouse models of
human disease. My present research focuses on epigenetic gene
regulation, on embryonic stem cells, and on nuclear cloning. Our focus
is understanding the mechanisms that bring about reprogramming of a
somatic nucleus to an embryonic one after its transfer into the egg. I
work with mice and our results have demonstrated that nuclear cloning
is inefficient, that most clones die at an early embryonic stage and
that the few that survive to birth and beyond harbor serious defects
and are not normal. The conclusion from this work is that reproductive
cloning of humans is an unsafe technology that should be banned.
Our work has shown that somatic cell nuclear transfer (SCNT) can
generate ``customized'' embryonic stem cells that can be used for the
treatment of genetic diseases. We have performed a ``proof of
principle'' experiment in mice that carry a specific mutation which
causes a defective immune system. Human patients with a corresponding
mutation (designated as Severe Combined Immune Deficiency or SCID) are
unable to fight infections and have a grim prognosis. In our proof of
principle experiment the nuclei of SCID mouse skin cells were
transplanted into enucleated eggs to generate cloned blastocysts (NT-
blastocysts) that were then placed into tissue culture to derive
``customized'' cloned embryonic stem cells (NT-ES cells). The genetic
mutation was corrected by gene targeting, the ``repaired'' NT-ES cells
were then induced to differentiate into blood stem cells and, when
transplanted back into the mutant mouse, restored immune function. I
believe that this proof of principle experiment is directly relevant
for the treatment of human blood diseases such as thalassemia, sickle
cell anemia or leukemia. The recent success by the Korean group (Hwang
et al.) indicates that nuclear transfer in humans is more efficient
than was assumed before and I believe that treatment of bone marrow
diseases will likely be one of the first human diseases that will be
treated with SCNT.
Embryonic stem cells have an enormous potential for therapy of
debilitating diseases such as cancer, diabetes, Parkinson's or other
degenerative diseases. To realize this therapeutic potential much
research is needed to learn how to differentiate the embryonic cells
into cells used for transplantation. I am confident that the
possibility to derive new ES cell lines from IVF embryos as debated in
Congress would enormously help this research.
I will focus on nuclear transfer (NT). In addition to its potential
for customized therapy, nuclear transfer derived ES cells would be an
extraordinary important tool to study complex diseases such as ALS or
Alzheimers in the test tube since ``customized'' ES cells derived from
a patient would carry all the genetic alterations that caused the
disease in the patient. The exciting prospect is that differentiation
of the ES cells in the culture dish may provide clues to what goes
wrong with the cells and how to establish therapies. This is not a
future promise but this could be done today using the technology
established by the Korean group that was the first to successfully
derive human stem cells from cloned blastocysts.
What are the concerns of those who oppose nuclear cloning in humans
for the purpose of generating ``customized'' embryonic stem cells for
research or for therapy? I believe the key concern is that the
derivation of an embryonic stem cell would necessarily involve the
destruction of the blastocyst and thus the destruction of potential
human life. The crucial question is: does the cloned blastocyst really
represent potential normal human life?
From all experience with cloned animals I would argue that the
cloned blastocyst has little if any potential to develop into a normal
baby as most would die in development and the few that survive will be
abnormal and will develop severe defects with age. This is because
reprogramming of the somatic cell's genome after nuclear
transplantation is a faulty process causing the great majority of
clones to have hundreds of genes incorrectly expressed. For these
reasons it has been suggested that, because the cloned blastocyst is so
different from the normal blastocyst derived from a fertilized egg, it
should not be designated as an ``embryo''--and I agree with this
notion. However, the cloned blastocyst has some chance, an exceedingly
small chance, to ever develop into a cloned animal such as Dolly. And
Dolly died early because she suffered from major ailments due to faulty
reprogramming as most if not all cloned animals do. It is this
statistically small chance of a clone to develop to birth and beyond
that troubles, I believe, those who are opposed to the NT technology.
The Altered Nuclear Transfer (ANT) approach has been proposed by
Dr. Hurlbut from Stanford as a potential solution for the ethical
dilemma. This approach would cause the product of nuclear transfer to
be inherently unable to ever develop into a fetus or a baby, because of
its inability to establish the very first step of embryonic
organization and its inability to establish a fetal-maternal
connection. With other words, the ANT procedure would reduce the
statistically low chance of an NT blastocyst to develop to birth to
zero. The procedure, as proposed by Hurlbut, involves the genetic
manipulation of the donor skin cell with the goal to inactivate a gene
that is required for embryo development if the nucleus of the
manipulated cell would be transplanted into an enucleated egg as in
SCNT. The manipulation would, however, have no ill effect on the
derivation of embryonic stem cells from the product of SCNT. Thus, the
alteration causes the somatic nucleus to function in such a way that no
embryo is generated but embryonic stem cells can be produced. The goal
of ANT is to generate a nuclear transfer product that lacks the
essential attributes of an embryo and has no potential whatsoever to
develop into a fetus but still could proliferate and give rise to
embryonic stem cells. ANT was suggested last year as a thought
experiment. We have now performed a proof of principle experiment in
the mouse (published this week in Nature) that validates the proposal.
In our experiment an RNAi construct that inactivates the Cdx2 gene
was introduced into skin cells. Cdx2 has a crucial function in the
establishment of the first embryonic lineage, the trophectoderm that is
established at the 16-cell stage and forms the placenta of the embryo.
Skin cells normally do not express the Cdx2 gene. But when used as
donors for nuclear transplantation, the ANT product is unable to
activate the gene and therefore unable to establish the trophectoderm
lineage. However, the product of nuclear transfer did proliferate and
formed an abnormal NT-blastocyst. The normal blastocyst consists of the
inner cell mass (which will form the embryo proper) and a cavity which
is surrounded by trophectoderm cells (which will form part of the
placenta). In contrast to the normal embryo, the ANT blastocyst
collapses because the trophectoderm cells are lacking. Importantly,
when placed into tissue culture, the ANT blastocyst generates embryonic
stem cells that have the full potential for differentiation and therapy
and thus are indistinguishable from embryonic stem cells that are
derived from a fertilized embryo.
Does the ANT procedure generate ``embryos'', even if only abnormal
ones? Our experiments clearly show that the Cdx2 deficient blastocyst
has no potential to implant and to ever develop into a fetus because it
lacks the trophectoderm lineage that gives rise to the placenta. Cdx2
is activated at the 8-cell stage and activation of this key gene is
prevented in the ANT product. Thus, the product of ANT-SCNT is already
molecularly different from the normal embryo at the 8-cell stage and
becomes morphologically abnormal within the next two cell divisions.
The placenta is an integral part of the embryo and not some component
that could be separated from the embryo. It is like the engine of a
car: one cannot separate the engine from the car and still call it a
car. Because the ANT product lacks essential properties of the
fertilized embryo, it is not justified to call it an ``embryo''.
It is important to emphasize that ANT is not an alternative to
nuclear transplantation but a modification of an experimentally highly
demanding process. It requires additional manipulations of the donor
cells that will complicate the logistics of an already complex
procedure, and this has raised concerns among many scientists. Also, it
has not been determined whether Cdx2 has a similar function on human
placentation as in mouse. Because the effect of gene inhibition on
human placentation cannot be directly tested, surrogate assays such as
in vitro differentiation of human ES cells are required to assess the
effect of CDX2 deficiency on human placental development. The
experiments in mice have shown a proof of concept of the ANT procedure.
It would be unfortunate, however, if the implementation of this
approach would delay the research on human SCNT.
Senator Specter. Thank you very much, Dr. Jaenisch.
Our next witness is Dr. Steven Teitelbaum, Professor of
Pathology at Washington University School of Medicine, an M.D.
from Washington University, residency at New York University.
Thank you very much for coming in today, Dr. Teitelbaum, and we
are interested in hearing your testimony.
STATEMENT OF STEVEN TEITELBAUM, M.D., WILMA AND ROSWELL
MESSING, PROFESSOR OF PATHOLOGY AND
IMMUNOLOGY, WASHINGTON UNIVERSITY SCHOOL OF
MEDICINE
Dr. Teitelbaum. Mr. Chairman, I thank the committee for the
honor of speaking to you today.
Mr. Chairman, I have been a physician scientist for more
than 30 years. I have authored in excess of 300 scientific
papers, and I am here to tell you that in my estimation we are
facing a unique opportunity in the form of embryonic stem cell
research to potentially alleviate the misery of our fellow
Americans with a number of presently incurable diseases. But to
get there, we must do the science.
Opponents of embryonic stem cell research often articulate
their position as a contest between adult and embryonic stem
cells. Mr. Chairman, this is not a contest between various
types of stem cells. It is a contest between us as a society
and disease. We should be moving forward on all fronts, adult,
embryonic, and umbilical cord stem cells to win the battle. The
tool is not important. What counts is curing our neighbors.
That said, because of their flexibility, embryonic stem
cells hold more promise to ameliorate presently incurable
diseases than any other approach. I stress the word ``promise''
because we are not there yet, and it is my belief that it will
be some time before we are positioned to safely use these cells
for therapy. But if scientists are prevented from exploring the
biology of human embryonic stem cells, we will never get there.
Mr. Chairman, as you know, human embryonic stem cells can
presently be obtained from two sources; namely, the spare
products of in vitro fertilization, which ultimately would be
destroyed, and by somatic cell nuclear transfer, also known as
SCNT or therapeutic cloning. Although both approaches hold
enormous therapeutic potential, I am particularly taken with
the promise of SCNT because it may alleviate the major
complication of tissue and cell transplantation, namely
rejection and its attendant life-threatening consequences.
Mr. Chairman, I am a bone biologist and physician, and as
such, I see many patients who have received organ and cell
transplants. These patients typically develop severe
osteoporosis and often have many fractures because of the harsh
medications they must take to prevent rejection of their
transplant. It is my hope that embryonic stem cells, generated
by SCNT, which contain the transplant recipient's own DNA will
reduce the necessity for these devastating anti-rejection
drugs.
But, Mr. Chairman, my hopes for SCNT are more personal and
harken back more than 20 years when I was a young assistant
professor. At that time, I became interested in a genetic
disease of the skeleton known as osteopetrosis, or marble bone
disease, and I want to tell you a story about a child who
profoundly impacted my life.
Osteopetrosis is a disease in which kids make too much
bone. Consequently, their skulls become very thick and compress
their brains and nerves, such as those leading to the eye. Bone
also overgrows the bone marrow, preventing formation of blood
cells. Until the story I am about to tell you, all kids with
the malignant form of osteopetrosis developed fatal
neurological complications, including blindness, and infections
due to bone marrow suppression. These children invariably died
in the first decade, most before the age of 5.
In the early 1980's, our team thought we had identified the
abnormal cell causing osteopetrosis and concluded it resided in
the bone marrow. We reasoned, therefore, that if we gave an
osteopetrotic infant a bone marrow transplant which contains
adult stem cells, we might cure the disease. We realized the
enormous risk of rejection, so we waited until we had a perfect
immunological match between the donor and recipient, in this
instance the 3-month-old little girl you see in the top
picture. So we gave this baby a bone marrow transplant and
achieved the first cure of this disease. The middle panel shows
her at 3 years of age, and the bottom picture, which is recent,
was taken upon her graduation from college. Senators, being
part of a team which was first to cure a fatal disease,
particularly that of children, is a doctor's dream. It does not
get any better.
You may be asking yourselves why this guy, who is here as
an advocate of embryonic stem cell research, is telling us
about his victory with adult stem cells. Senators, I am
recounting the story to underscore the importance of moving
forward on all fronts because, regrettably, there is a down
side to my tale. You will remember that this was a perfect
immunologic match, and therefore there was little chance of
rejection. Unfortunately, such matches are extremely rare and
therefore, we presently cure less than 10 percent of kids with
osteopetrosis. The use of SCNT, in which embryonic stem cells
contain the patient's own DNA, if successful, would markedly
increase the cure rate of this disease.
PREPARED STATEMENT
Mr. Chairman, because of my familiarity with osteopetrosis,
I am frequently contacted by parents with afflicted children. I
have to tell them that the chances of curing your child is no
more than 10 percent. I want to tell them it is greater than 90
percent. SCNT, if we pursue it, may get us there.
Thank you.
[The statement follows:]
Prepared Statement of Dr. Steven Teitelbaum
Thank you Mr. Chairman. My name is Steven Teitelbaum. I'm the Wilma
and Roswell Messing Professor of Pathology and Immunology at Washington
University School of Medicine and I thank the committee for the honor
of speaking to you today.
Mr. Chairman, I've been a physician-scientist for more than 30
years. I've authored in excess of 300 scientific papers and I'm here to
tell you that, in my estimation, we are facing a unique opportunity in
the form of embryonic stem cell research, to potentially alleviate the
misery of our fellow Americans with a number of presently incurable
diseases. But to get there, we must do the science.
Opponents of human embryonic stem cell research often articulate
their position as a contest between adult an embryonic stem cells. Mr.
Chairman, this is not a contest between various types of stem cells. It
is a contest between us as a society and disease. We should be moving
forward on all fronts, adult, embryonic and umbilical cord stem cells,
to win the battle. The tool is not important. What counts is curing our
neighbors.
That said, because of their flexibility, embryonic stem cells hold
more promise to ameliorate presently incurable diseases than any other
approach. I stress the word ``promise'' because we are not there yet
and it is my belief that it will be some time before we are positioned
to safely use these cells for therapy. But if scientists are prevented
from exploring the biology of human embryonic stem cells, we will never
get there.
Mr. Chairman, as you know, human embryonic stem cells can presently
be obtained from two sources, namely the spare products of in vitro
fertilization, which ultimately would be destroyed, and by somatic cell
nuclear transfer, also known as SCNT or therapeutic cloning. Although
both approaches hold enormous therapeutic potential, I'm particularly
taken with the promise of SCNT because it may alleviate the major
complication of tissue and cell transplantation, namely rejection and
its attendant life threatening consequences.
Mr. Chairman, I'm a bone biologist and physician and as such I see
many patients who have received organ and cell transplants. These
patients typically develop severe osteoporosis and often have many
fractures because of the harsh medications they must take to prevent
rejection of their transplant. It is my hope that embryonic stem cells,
generated by SCNT, which contain the transplant recipient's own DNA,
will reduce the necessity for these devastating anti-rejection drugs.
But Mr. Chairman, my hopes for SCNT are more personal and hearken
back more than 20 years when I was a young assistant professor. At that
time I became interested in a genetic disease of the skeleton known as
osteopetrosis or marble bone disease and I want to tell you a story
about an afflicted child who profoundly impacted my life. Osteopetrosis
is a disease in which kids make too much bone. Consequently, their
skulls become very thick and compress their brains and nerves, such as
those leading to the eye. Bone also overgrows the bone marrow
preventing formation of blood cells. Until the story I'm about to tell
you, all kids with the malignant form of osteopetrosis developed fatal
neurological complications, including blindness, and infections due to
bone marrow suppression. These children invariably died in the first
decade, most before the age of five.
In the early 80s, our team thought we had identified the abnormal
cell causing osteopetrosis and concluded it resided in the bone marrow.
We reasoned, therefore, that if we gave an osteopetrotic infant a bone
marrow transplant, which contains adult stem cells, we might cure the
disease. We realized the enormous risk of rejection so we waited until
we had a perfect immunological match between the donor and recipient,
in this case a 3 month old little girl you see in the top picture. So
we gave this baby a bone marrow transplant and achieved the first cure
of this disease. The middle panel shows her at 3 years of age and the
bottom picture, which is recent, was taken upon her graduation from
college. Senators, being part of a team which is first to cure a fatal
disease, particularly of children, is a doctor's dream. It doesn't get
any better.
You may be asking yourselves why this guy, who is here as an
advocate of embryonic stem cell research, is telling us about his
victory with adult stem cells. Senators, I'm recounting the story to
underscore the importance of moving forward on all fronts because
regrettably there is a downside to my tale. You'll remember that this
was a perfect immunological match and therefore there was little chance
of rejection. Unfortunately, such matches are extremely rare and
therefore we presently cure less than 10 percent of kids with
osteopetrosis. The use of SCNT, in which embryonic stem cells contain
the patient's own DNA, if successful, would markedly increase the cure
rate of this disease. Mr. Chairman, because of my familiarity with
osteopetrosis I'm frequently contacted by parents with afflicted
children. I have to tell them the chances of curing your child is no
more than 10 percent. I want to tell them it's greater than 90 percent.
SCNT, if we pursue it, may get us there.
Senator Specter. Thank you very much, Dr. Teitelbaum.
Our final witness is Dr. John Wagner, Professor of
Pediatrics and Scientific Director of the Stem Cell Institute
at the University of Minnesota. An M.D. at Jefferson Medical
College in Philadelphia and internship and residency at Duke
University School of Medicine. Thank you for coming to
Washington today, Dr. Wagner, and we look forward to your
testimony.
STATEMENT OF JOHN WAGNER, M.D., SCIENTIFIC DIRECTOR OF
CLINICAL RESEARCH, BLOOD AND MARROW
TRANSPLANT PROGRAM AND STEM CELL INSTITUTE
Dr. Wagner. Mr. Chairman and committee members, I am coming
here as a clinician, as a stem cell researcher. It is not a
question of whether or not this knowledge is going to be
translated into something clinically useful. The real question
is, when is that going to happen?
The work should not be restricted to private industry. Stem
cell research should be taking place in academic institutions,
supported by Federal dollars with guaranteed oversight, peer
review, and transparency.
Right now, as we have heard already in testimony this
morning, there is only one proven use of stem cells and that is
in the context of blood and marrow transplantation to treat
diseases like leukemia, lymphoma, sickle cell disease, and a
variety of other blood and immune disorders. In these
instances, we need to infuse stem cells to repair the marrow
that has been destroyed either by the disease itself or by the
therapy we use to treat that disease, such as with chemotherapy
and irradiation. These blood-producing stem cells are found in
marrow and they are found in cord blood, which is the blood
that is left in the placenta after a baby is born.
Tremendous achievements have already been made in these
areas, particularly in the area of cord blood most recently,
and in fact, the Institute of Medicine last April made
recommendations that we significantly augment the Nation's
inventory of cord blood to help take care of our patients
around the country.
While my own work is focused on the development of stem
cell therapies from cord blood or adult tissues and, perhaps
surprisingly, not embryonic stem cells, I am here today really
to defend ES cell work. It must be unequivocally clear that our
work in cord blood and adult stem cells does not eliminate the
need for work in ES cells. Yes, it is true that stem cells and
cord blood and adult tissues can differentiate into perhaps the
lining cells of the gut or the liver or neural tissue, but they
do not exhibit all the capacities of ES cells. For example, we
have yet to see stem cells from cord blood or adult tissues
differentiate into heart muscle that spontaneously beats in the
petri dish. That has been shown repetitively by people working
on ES cells.
The University of Minnesota is well known for its work in
adult stem cells in umbilical cord blood, and with Catherine
Verfaille, we have pioneered that work in cord blood and
multipotent adult stem cells and we see great promise in those
areas. But we recognize, although there is tremendous
potential, there are also limitations.
It is critical that you also know that every discovery that
has occurred with ES cells has really benefitted us working on
adult stem cells and cord blood.
But speaking as a clinician who creates these new stem cell
therapies for treating children and adults with a variety of
``incurable'' diseases, it not only gives us significant hope,
but it also comes with risk. This winter we hope to be able to
try our first stem cell transplants in the treatment of
patients damaged by chemotherapy and irradiation, not just for
bone marrow recovery, but also the other tissues that are
involved in the treatment and damaged by it. We have to go
through the ethics committees, we have to go through human
subjects committee, and the FDA. But we are going to move this
therapy forward, obvious, with all the proper oversight.
But it is incomprehensible that we do otherwise, that we
restrict ourselves to one type of stem cell. Like others in
this room, I feel compelled to move this forward on behalf of
the thousands of patients that write to me every week asking to
allow them to be the first stem cell recipient. In fact, this
is just one e-mail that I received yesterday from a woman who
is 39 years old saying, I had a stroke several years ago. What
can you do for me? Let me be the first. Why can I not be a
healthy wife to my husband, a mother to my young child?
Is this all hype? Where are the first trials with ES cells?
Certainly the lack of funding and restricted access to suitable
stem cell lines has been a major barrier in our research
efforts. We need to address those barriers where possible. For
example, can we separate reproductive cloning from nuclear
transfer? If you desire rapid translation of ES cells into real
clinical therapies, let us not restrict it. We need to be able
to use nuclear transfer because it is likely to be instrumental
in moving that therapy forward as quickly as possible.
Again, this is not some scientist's dream. It has been done
with human cells, at least in South Korea. Every single one of
us will be faced with a disease amenable to stem cell therapy.
It may be our child, our spouse, our friend, or even ourselves,
and you can ask Mr. Herrera and you can ask Ms. Carolyn Kohn,
who is in the audience, who had a child die of aplastic anemia.
Cord blood certainly has its proven benefits in the
treatment of a variety of diseases. It has great potential
perhaps in the future for tissue repair that yet has clearly to
be identified. Federal dollars should be devoted to the work of
all these stem cell sources, including ES cells. ES cell work
must continue in parallel.
PREPARED STATEMENT
As a clinician that treats these patients who are defined
as incurable, I feel obligated to be here on their behalf. I am
sure that many of them are anxiously waiting to hear what
happens today. For them, the stakes must be simply
unimaginable.
[The statement follows:]
Prepared Statement of Dr. John E. Wagner
Stem cell therapy will revolutionize the practice of medicine. For
the first time there will be treatments for spinal cord injury,
diabetes, cancer, stroke, and heart disease with potentially long term
benefits. The proof of principle already exists.
It is not a question of whether this new knowledge will translate'
into clinical therapies but rather how long. Will clinical trials in
diabetes or stroke be soon or decades away? Will this work be driven by
private industry without any oversight or in academic environments
using federal support; conducted in university settings which guarantee
requisite oversight, publication, peer review and transparency?
So what do we know about stem cells today?
There is only one proven established use of stem cells and that is
in the setting of bone marrow transplantation. For decades it has been
known that marrow stem cells can be transplanted from one individual to
another in order to replace the blood and marrow of patients with
leukemia/lymphoma/multiple myeloma/other diseases after their own
marrow has been destroyed by disease or treatment with high doses of
chemotherapy and radiation. These stem cells come from adult marrow or
umbilical cord blood.
My own work is focused on umbilical cord blood and development of
novel phase I clinical trials. In this discussion, we cannot forget
that cord blood is already an established treatment with tremendous
potential. Recently, the Institute of Medicine summarized its findings
on the benefits of cord blood and the urgent need to expand the useable
inventory. Cord blood is rapidly becoming the standard of care in
children. We have recently reported outcomes in adults with results
that are unprecedented. However, it must be clear that cord blood stem
cells are not the stem cells found in embryonic stem cell lines. The
stem cells in adult tissues and umbilical cord blood have different
properties and may or may not have unlimited differentiation capacity.
While it is hoped that one day we will be able to take adult tissue or
cord blood stem cells and trick it to become ``ES-like'', this is not
yet possible. Despite what the opponents to ES cell work would suggest,
it is simply not true.
The University of Minnesota is well known in the field of stem cell
research. We have the longest standing Stem Cell Institute in the
country. My work in umbilical cord blood stem cell research and
Catherine Verfaillie's work on the multipotent adult stem cell clearly
demonstrate our hope to maximize the potential of cord blood and adult
tissue stem cells but we recognize that there are limitations. Of
course we are excited about the future potential of these stem cells
but never have we suggested that they obviate the need for ES cell
research. For example, never have the stem cells from cord blood or
adult tissues ever produced heart muscle cells that spontaneously beat
or formed islets that secrete insulin, as has been shown repeatedly
with ES.
It is critical for the public to know that if we are ever to make
cord blood and adult tissue stem cells function like ES cells, we need
to study ES cells. Every discovery with ES cells has furthered our work
with stem cells from umbilical cord blood or adult tissues.
Now speaking as a clinician who actually performs new therapies
with stems cells in humans, we are indeed planning to perform the first
clinical trial with multipotent adult stem cells this winter in an
attempt to repair tissues damaged by radiation and chemotherapy. My
goal is to move stem cell therapy forward in numerous areas as the
clinical director of the Stem Cell Institute. Once we meet the
requirements of the Human Subjects Committee, FDA, Ethics committees,
we plan to move stem cell therapies forward regardless of whether they
are ES, cord blood or adult tissue-derived. It is incomprehensible to
do otherwise. Like others, I receive thousands of letters, emails,
phone calls per month asking me to allow them to be the first to
receive stem cell treatments--these people have cancer, spinal cord
injury, diabetes, strokes, Parkinson's disease, and other genetic
diseases. (Show sample emails from this week).
You ask, what is the future of ES cells to cure a disease--the
answer is simply ``breathtaking''. Clearly there are risks as ES cells
if left undifferentiated have a propensity to cause tumors. But still,
many are working to make these cells therapeutically valuable. In
addition to the development of novel strategies for treating
Parkinson's, diabetes, stroke and spinal cord injury, some like Daniel
Kaufman at the University of Minnesota are focused on manufacturing red
blood cells in massive scale thus reducing our dependence upon
volunteer donors or developing nature killer cells as anticancer
agents-both derived from ES cells. So why has there not been a single
trial thus far with ES cell--funding, access to suitable cells lines,
and research on the immune response to these stem cells. Nuclear
transfer will be crucial to this success--``tailor made'' stem cells
lines for individuals will be required to counter likely immune
responses. Again, this is not futuristic, the South Korean scientists
have clearly demonstrated that this is not just desirable but possible.
To restrict work with ES cells or bar SCNT would cripple our
capacity to move all stem cell therapies forward ES cells are the gold
standard and research with them will maximize the potential of cord
blood and adult stem cells and pursuit of multiple approaches will
permit the most rapid translation of stem cells possible into
efficacious clinical therapies. Every single one of us will be faced
with a child, friend, loved one, or even ourselves with a disease
amenable to stem cell therapy in the not too distance future. Umbilical
cord blood has proven benefits in the treatment of leukemia, lymphoma,
blood disorders, immune deficiencies and metabolic diseases today.
Banking of cord blood is in the nation's interest and federal dollars
should continue to be spent to determine the breadth of what it can
offer well beyond the confines of blood and marrow diseases. At the
same time in parallel, we must also push ES and adult stem cells to the
limits of what they can offer. And for ES cells, banning SCNT could
prevent its future success as SCNT is likely to be the key that will
make ES cell therapies more widely available more rapidly. I am here as
an advocate for the thousands of people who have asked me to push this
forward.
Senator Specter. Thank you very much, Dr. Wagner.
Mr. Herrera, you have testified about your situation being
a medical breakthrough in medical history. Was the aspect of
using stem cells on your lymphoma the unique breakthrough that
you referred to?
Mr. Herrera. Without question. The difference between the
first transplant and the second transplant was at the first
transplant, they took stem cells out of my body. I injected
myself with a drug called Neupogen every day. This causes the
bone marrow to over-produce. Little baby stem cells are
floating around in the blood. They stick a pipe in here, run it
through a machine, and they take out the little baby stem
cells.
The problem with that transplant for mantle cell lymphoma,
which they were not aware of at the time, was this is my immune
system.
So the theory of the allogeneic stem cell transplant--I go
back to my Mississippi roots--we are having civil disorder in
Wiggins, Mississippi, so we call out the Stone County National
Guard. I am told not to let anybody cross this line. Winfield
Alexander wants to cross the line. I cannot stick Winfield in
the gut with a bayonet because he was my Boy Scout leader in
the rattlesnake patrol. But if you bring in the National Guard
from Montana, they speak the same language, they can read the
signs, and they are not going to have a problem sticking
Winfield with a bayonet. So the foreign immune system is going
to be tougher on the lymphoma, on the blood cancer, because it
does not know it that well. That is kind of a basic comment,
but that is how I had to understand it.
Senator Specter. Thank you, Mr. Herrera.
I very much regret that I am going to have excuse myself at
this point. I turn the gavel over to Senator Cochran.
What I would appreciate your doing, each of you, is to
write a memo or a letter to the subcommittee as to what you
could do if Federal funding were available for your stem cell
research. Dr. Gasson is from UCLA where I visited several years
ago. Without the particulars at hand, I know UCLA is the
beneficiary of very substantial NIH grants.
This subcommittee, Senator Harkin, Senator Cochran, and
then the full committee has taken the lead in increasing
Federal funding from $12 billion to $28 billion. And we are now
on the cutting edge.
Dr. Wagner, you talked about use of Federal funds.
I regret that there are not more Senators available, but
this is the third time it will be said. This is a very, very
busy place, but your testimony is transcribed. Staff are here
and Senators will review it. If you would supplement what you
have testified to, Dr. Teitelbaum, Dr. Jaenisch, Dr. Wagner,
Dr. Gasson, with what the Federal funding could do. We are
going to have a vote on this one day soon, without going into
all the technicalities. And the evidence that you will present
will be very helpful when we fight it out on the Senate floor.
Things are quiet here today, but we are going to have a pretty
heavy debate on this subject and your participation and your
evidence will be very, very helpful in achieving a very, very
important goal for medical science.
Senator Cochran, let me thank you for taking the gavel. It
belongs to you anyway.
Senator Cochran [presiding]. Thank you for your patience
with our change of command and responsibility.
I appreciate so much each of your efforts to be here today,
to take time to prepare a presentation for our committee so
that we can better understand the challenges and the
responsibilities that we have for identifying ways that we can
continue to support medical research, to take those actions
that will help find cures for diseases, prevent diseases. So
this is all very serious business, and I appreciate very much
the fact that you have taken time and devoted your efforts and
energies to this hearing today.
Senator Specter, as I said in my opening comments, has been
a champion for medical research, and the figures that he cites,
the increase in the funding that we have been able to provide
or to recommend--we do not get to decide. We recommend to the
full committee. The full committee approves and recommends to
the Senate, and we have to work out differences between the
Senate and the House. But it has been a successful campaign to
more than double the amount of money that is available for
researchers and those providing treatment in our battle to find
cures and to prevent disease, particularly cancer.
Let me ask a few questions. I understand, Dr. Teitelbaum,
you are at the Washington University School of Medicine and
have completed a residency at New York University. Let me ask
you. What would you say is the overwhelming opinion of
scientists regarding the need to expand the current stem cell
policy? Is there any disagreement within the community?
Dr. Teitelbaum. I think not, Senator. I think that the
overwhelming opinion of scientists is to move forward on all
fronts, that there is potential in adult stem cell research,
embryonic stem cell research, and umbilical cord blood stem
cell research. We cannot determine which technique will yield
what results until we do the science.
Senator Cochran. Dr. Gasson, I heard your comments, before
I had to step out of the hearing room, in your opening
statements. What forms of cancer do you think will be the most
responsive to drugs developed using stem cells?
Dr. Gasson. We believe that those types of cancer that have
been shown experimentally to be derived from a mutated adult
stem cell would be the very best targets for those small
molecules. Fortunately or unfortunately for us, they include
some of the most common forms of cancer, such as breast cancer,
prostate, colon, some of the leukemias, and as you are probably
quite well aware, brain tumors which are truly devastating.
We think that the concept of the cancer stem cell explains
a lot about the natural history of the disease. The patient
develops cancer and is treated with surgery, radiation, perhaps
chemotherapy, and the bulk of the tumor, the large mass of the
tumor goes away. But for some patients over the next 2, 3, 4,
or 5 years, the tumor comes back and the tumor that recurs is
typically even more aggressive. And we think this is because
the treatments that we have now do not kill the tumor stem
cell, and so slowly it begins to divide and it recreates the
tumor cells in the patient. And now those cells are even more
resistant to the treatments that we have. So until and unless
we are able to either destroy the cancer stem cell, or at least
keep it under control, we will be continuing to face the
possibility of recurrence in these very common and very deadly
cancers.
Senator Cochran. Dr. Jaenisch, there was some indication in
a Washington Post article that the altered nuclear
transplantation technique that your lab has achieved may be a
way around the objections of some who oppose embryonic stem
cell research. Would you have pursued this line of research if
not for the restrictions in place on stem cell research?
Dr. Jaenisch. I think our research had two goals. One is a
scientific one. We wanted to see whether these cells can do
what we thought they could do. But I think the major goal was
to find a potential compromise which could compromise between
the concerns of those who object to the nuclear transfer
procedure and those who think that is really important to do.
So I think the altered nuclear transfer procedure is a
modification of the nuclear transfer procedure. It is an
additional step which complicates an already complex procedure.
But from our experience with mice at least, it is such a
straightforward and simple modification that it may be
acceptable as a compromise if that would allow then this
research to go on and to provide the funding for this type of
research.
Senator Cochran. Is the kind of research you are doing
susceptible to funding by the National Institutes of Health?
Dr. Jaenisch. All my research is funded by the National
Institutes of Health, but I work with mice, so it is not
controversial. But we would like to move into human cells. We
would like to work with the new human stem cells. We would like
to understand how the human cells compare with the mouse cells,
and we are very limited. We do not have funding for that.
Senator Cochran. Well, do you think that Federal funding
should be diverted from other forms of stem cell research to
support alternative methods to derive stem cells?
Dr. Jaenisch. Well, I am not sure if it should be diverted.
As was said by all the speakers here, we really need to pursue
all these avenues. So alternative methods--several have been
proposed.
I think the final goal of the field in my opinion is to
understand what reprogramming means. How does the egg reprogram
a somatic nucleus and eventually do it without the egg. In
order to get there, we need the egg. We need human eggs to
learn how the human egg does reprogramming. So I think it is
counterproductive for this goal at this point that research is
not allowed to use human eggs.
Senator Cochran. Anthony, I am so pleased that you were
able to be here today to put in perspective from a patient's
point of view how important research in the development of new
treatments, finding new ways of dealing with these medical
problems will be, and the role that we can play. I know if you
had a vote, you would probably vote to quadruple, double,
exponentially increase funding.
But where in the area of research from your experience do
we need to supplement and try to provide more incentives
through Federal research appropriations to achieve the goals of
curing cancers like yours?
Mr. Herrera. What these ladies and gentlemen up here have
said is that there should be massive amounts, billions of
dollars, and no restrictions on any of this research because I
have met with the doctor at M.D. Anderson--Andreyev I believe
is his name--and we were talking about the embryonic versus the
adult. He said we need lots of room to experiment.
The drug that helped save my life, which has probably saved
hundreds of thousands of lives, Neupogen, was developed by
Janice Gabrilove and two other doctors. She was in charge of my
first bone marrow transplant. I said, how did you develop this
drug? She said we did not have a straight line. We were in
there in that region working, and all of a sudden there was a
path we could follow.
So there needs to be no restriction. There needs to be
massive amounts of money. South Korea, Singapore 2 years ago
were ahead of us. China just put billions of dollars into
research. So there should be no restrictions and massive
amounts of money put behind this in my opinion.
Senator Cochran. From your experience, could you tell us in
your own words what the difference is from a patient's point of
view in a bone marrow transplant therapy and a stem cell
transplant therapy?
Mr. Herrera. Actually--someone please correct me if I am
wrong--they are the same thing except the way you get the cell.
The reason it is called a bone marrow transplant is before this
drug Neupogen and before the apheresis machine, they had to
drill into the bone marrow to suck out marrow and then get the
stem cell out of that. Am I correct on that? So it evolved into
simply being called the stem cell transplant. Some hospitals
still drill into the bone and suck out the marrow to get the
stem cell, but they are ultimately the same thing.
Senator Cochran. It does not sound like much fun.
Mr. Herrera. There was not a lot of fun through the whole
process, Senator.
Senator Cochran. I can remember reading your description of
the pain that you suffered in that first effort to get some of
your bone marrow. No anesthetic.
Mr. Herrera. That was not good medicine.
Senator Cochran. I hope that is not a widespread practice
now.
Mr. Herrera. I have learned that it is not.
Senator Cochran. Good.
Dr. Wagner, we appreciate your being here as well. Since
your primary interest appears to be cord blood stem cell
research, as I understand it, why are you so supportive of
embryonic stem cell and nuclear transplantation research?
Dr. Wagner. My interest is, obviously, in cord blood as one
avenue. As the clinical director of the Stem Cell Institute, I
am really interested in all aspects of stem cell therapies,
whether it comes from embryonic stem cells, adult tissues, or
umbilical cord blood. So we are exploring all avenues.
However, my own personal research area in the laboratory is
with umbilical cord blood and trying to figure out what really
the breadth of applicability will be. So we are investigating
not only in the context of classical bone marrow
transplantation, which has proven to be of great use, but also
looking at what its differentiation potential is, can it
differentiate into various tissues.
But remember that what we said over and over again is that
ES cells are the gold standard by which everything is compared.
And everything that we have learned with embryonic stem cells,
in terms of the mechanisms of what makes them able to become
liver or lung or brain, or whatever it is, has given us clues
or techniques that allow us to see if we can get adult tissues
or cord blood tissues to do the same thing. So without having
that research move forward with embryonic stem cells, we have
no hope to make adult tissues or cord blood stem cells become
you would all like it to become as the stem cell source.
Senator Cochran. Does it surprise you that the NCI funds
less than $5 million worth of embryonic stem cell research? And
why do you think the level of stem cell research is so low in
the context of a $5 billion budget?
Dr. Wagner. You are asking my opinion now.
Senator Cochran. Yes.
Dr. Wagner. Well, clearly, I think the reason why the
budget is so low is, in part, related to the ethical issues
associated with embryonic stem cell work. However, there is
considerable funding for adult tissue stem cells, as well as
umbilical cord blood. However, what we need to be doing is
working on embryonic stem cells. Unfortunately, the budget is
low and it has actually been extraordinarily restrictive in
what we are able to do.
Right now as the clinician that hopes to move some of these
cell therapies forward, we have no hope of using the existing
stem cell lines that are currently approved because of the fact
that many of them were developed on murine feeder layers or
they have cytogenetic abnormalities having been passaged in a
culture. And as someone who manufactures cells for clinical
use, they would never fulfill our criteria. So certainly we
need to markedly expand the amount of resources or else we will
never be able to move it forward.
Senator Cochran. Dr. Gasson, you also lead an NCI-
designated comprehensive cancer center and support research on
embryonic stem cells. Do you have an opinion about the
disparity in terms of the $5 million for stem cell research
compared with a $5 billion budget?
Dr. Gasson. I have two additional thoughts to add to Dr.
Wagner's comments.
First of all, this notion that cancer arises from a cancer
stem cell is fairly new. If you are trying to study the cancer
stem cell, that is an adult stem cell, and so that particular
type of work has just recently been done and probably would not
be counted under the rubric of embryonic stem cell research.
But the main reason is the reason that Dr. Jaenisch
articulated, which is most of the people that are trying to
work in this field are working with mouse ES cells and mouse
models because of the restrictions on the use of human ES
cells. And Dr. Jaenisch is a perfect example. These people are
extraordinarily talented. They have devoted their careers to
understanding these things. If we could channel them from the
mouse to working on human ES cells, we could accelerate the
pace of progress enormously. So it is a follow-up on Dr.
Wagner's answer, which is that the restrictions are pushing
people to work in the mouse system.
CONCLUSION OF HEARING
Senator Cochran. Let me thank all of you for your generous
contribution of time and effort to this hearing. We appreciate
it very much, and I am sure we will benefit from your
observations and your wisdom as we proceed through the
appropriations process for writing a bill that actually is
going to come to the floor next week possibly. This will be the
last appropriations bill considered by the Senate this year. So
we want to be sure we have our facts and arguments available to
describe the reasons why we think funding of additional medical
research is so important to the future of our country and
mankind. Thank you for the contribution you have made to that
effort.
The hearing is recessed.
[Whereupon, at 10:31 a.m., Wednesday, October 19, the
hearing was concluded, and the subcommittee was recessed, to
reconvene subject to the call of the Chair.]
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