Lymphoma is the fifth most common cancer in the United States and represents over forty subtypes of cancers arising within the lymphatic system. The two most prevalent types are Hodgkin's and non-Hodgkin's lymphomas. Of the 63,700 estimated new cases of lymphoma in 2005, non-Hodgkin’s lymphoma accounts for about 88 percent of those cases. The incidence of non-Hodgkin’s has increased, nearly doubling over the past 30 years. Researchers speculate that the increase may be due in part to environmental agents triggering genetic factors which initiate malignancies. Hodgkin’s lymphoma, with 7,000 new cases predicted in 2005, is a less prevalent disease. The cause of most lymphomas is unknown, but a compromised immune system and exposure to carcinogens, bacteria and viruses may play a role. The incidence of lymphoma is increased in patients infected with Epstein-Barr virus (which causes mononucleosis) or HIV.

Lymphomas result when cells in the immune system multiply uncontrollably. The immune system is maintained by lymphocytes; T-cells and B-cells, each playing specific roles in fighting disease...

Multiple myeloma is a cancer of plasma cells. Normal plasma cells, which are derived from B-lymphocytes (a type of white blood cell), are typically found within bone marrow. Their role in the immune system is to secrete large amounts of immunoglobulin proteins (antibodies) to circulate in the blood. Each plasma cell secretes only one kind of antibody (monoclonal immunoglobulin), but a collection of different plasma cells secrete many kinds of antibodies (polyclonal immunoglobulin). When foreign substances such as bacteria or viruses enter the body, they specifically stimulate lymphocytes to become a type of plasma cell that secretes polyclonal antibodies. These antibodies can then attack and neutralize foreign invaders, thus preventing infection and disease.