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  G



G-CSF  
A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called filgrastim and granulocyte colony-stimulating factor.

gabapentin  
A substance that is being studied as a treatment for relieving hot flashes in women with breast cancer. It belongs to the family of drugs called anticonvulsants.

GAD  
A condition marked by excessive worry and feelings of fear, dread, and uneasiness that last six months or longer. Other symptoms of GAD include being restless, being tired or irritable, muscle tension, not being able to concentrate or sleep well, shortness of breath, fast heartbeat, sweating, and dizziness. Also called generalized anxiety disorder.

gadolinium  (GA-duh-LIH-nee-um)
A metal element that is used in magnetic resonance imaging (MRI) and other imaging methods. It is a contrast agent, which helps show abnormal tissue in the body during imaging with a special machine.

gadolinium texaphyrin  (GA-doh-LIH-nee-um tek-SA-fih-rin)
A substance that is being studied in the treatment of cancer. It may make tumor cells more sensitive to radiation therapy, improve tumor images using magnetic resonance imaging (MRI), and kill cancer cells. It is a type of metalloporphyrin complex. Also called motexafin gadolinium.

gadopentetate dimeglumine  (GAD-oh-PEN-teh-tayt dy-MEG-loo-meen)
A substance used in magnetic resonance imaging (MRI) to help make clear pictures of the brain, spine, heart, soft tissue of joints, and inside bones. Gadopentetate dimeglumine is being studied in the diagnosis of cancer. It is a type of contrast agent. Also called Gd-DTPA and Magnevist.

Gail model  
A computer program that uses personal and family history to estimate a woman’s chance of developing breast cancer.

galiximab  (gal-IX-ih-mab)
A monoclonal antibody that is being studied in the treatment of follicular non-Hodgkin lymphoma. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. Galiximab binds to the protein CD80, which is found on certain normal and cancerous white blood cells.

gallbladder  (GAWL-bla-der)
The pear-shaped organ found below the liver. Bile is concentrated and stored in the gallbladder.

gallbladder cancer  (GAWL-bla-der KAN-ser)
Cancer that forms in tissues of the gallbladder. The gallbladder is a pear-shaped organ below the liver that collects and stores bile (a fluid made by the liver to digest fat). Gallbladder cancer begins in the innermost layer of tissue and spreads through the outer layers as it grows.

gallium nitrate  
A drug that lowers blood calcium. Used as treatment for hypercalcemia (too much calcium in the blood) and for cancer that has spread to the bone (bone metastases).

gallium scan  
A procedure to detect areas of the body where cells are dividing rapidly. It is used to locate cancer cells or areas of inflammation. A very small amount of radioactive gallium is injected into a vein and travels through the bloodstream. The gallium is taken up by rapidly dividing cells in the bones, tissues, and organs and is detected by a scanner.

gallstone  
Solid material that forms in the gallbladder or common bile duct. Gallstones are made of cholesterol or other substances found in the gallbladder. They may occur as one large stone or as many small ones, and vary from the size of a golf ball to a grain of sand. Also called cholelith.

galvanic skin response  (gal-VA-nik ... reh-SPONTS)
A change in the heat and electricity passed through the skin by nerves and sweat. Galvanic skin response increases in certain emotional states and during hot flashes that happen with menopause. Also called electrodermal response and skin conduction.

gamma irradiation  
A type of radiation therapy that uses gamma radiation. Gamma radiation is a type of high-energy radiation that is different from x-rays.

Gamma Knife therapy  
A treatment using gamma rays, a type of high-energy radiation that can be tightly focused on small tumors or other lesions in the head or neck, so very little normal tissue receives radiation. The gamma rays are aimed at the tumor from many different angles at once, and deliver a large dose of radiation exactly to the tumor in one treatment session. This procedure is a type of stereotactic radiosurgery. Gamma Knife therapy is not a knife and is not surgery. Gamma Knife is a registered trademark of Elekta Instruments, Inc.

gamma ray  
A type of high-energy radiation that is different from an x-ray.

ganciclovir  
An antiviral agent used to prevent or treat cytomegalovirus infections that may occur when the body's immune system is suppressed. In gene therapy, ganciclovir is used with an altered herpes simplex virus-1 gene to kill advanced melanoma cells and brain tumor cells.

ganglioside  
A complex molecule that contains both lipids (fats) and carbohydrates (sugars) and is found in the plasma (outer) membrane of many kinds of cells. Several different types of gangliosides have been identified.

garden heliotrope  
A plant whose roots are used as a sedative and to treat certain medical conditions. It is being studied as a way to improve sleep in cancer patients undergoing treatment. Also called garden valerian, Indian valerian, Mexican valerian, Pacific valerian, valerian, Valeriana officinalis, and Valerianae radix.

garden valerian  
A plant whose roots are used as a sedative and to treat certain medical conditions. It is being studied as a way to improve sleep in cancer patients undergoing treatment. Also called garden heliotrope, Indian valerian, Mexican valerian, Pacific valerian, valerian, Valeriana officinalis, and Valerianae radix.

garlic  (GAR-lik)
A European plant that has a bulb used to flavor food. It has also been used in some cultures to treat certain medical conditions including high cholesterol, high blood pressure, infections, and cancer. The scientific name is Allium sativum.

gastrectomy  (ga-STREK-toh-mee)
An operation to remove all or part of the stomach.

gastric  (GAS-trik)
Having to do with the stomach.

gastric atrophy  (GAS-trik AT-ro-fee)
A condition in which the stomach muscles shrink and become weak. The digestive (peptic) glands may also shrink, resulting in a lack of digestive juices.

gastric cancer  (GAS-trik KAN-ser)
Cancer that forms in tissues lining the stomach. Also called stomach cancer.

gastric mucosal hypertrophy  (GAS-trik myoo-KOH-sul hy-PER-troh-fee)
A condition marked by inflammation and ulcers (breaks on the skin or on the surface of an organ) of the mucosa (inner lining) of the stomach and by overgrowth of the cells that make up the mucosa. Symptoms include vomiting, diarrhea, and weight loss. Patients with gastric mucosal hypertrophy may be at a higher risk of stomach cancer. Also called giant hypertrophic gastritis and Ménétrier disease.

gastric reflux  
The backward flow of stomach acid contents into the esophagus (the tube that connects the mouth to the stomach). Also called esophageal reflux and gastroesophageal reflux.

gastrin  (GAS-trin)
A hormone released from special cells in the lining of the stomach after eating. Gastrin causes the stomach to release an acid that helps digest of food.

gastrinoma  (gas-trih-NOH-muh)
A tumor that causes overproduction of gastric acid. It usually begins in the duodenum (first part of the small intestine that connects to the stomach) or the islet cells of the pancreas. Rarely, it may also begin in other organs, including the stomach, liver, jejunum (the middle part of the small intestine), biliary tract (organs and ducts that make and store bile), mesentery, or heart. It is a type of neuroendocrine tumor, and it may metastasize (spread) to the liver and the lymph nodes.

gastritis  
Inflammation of the lining of the stomach.

gastroenterologist  (GAS-troh-EN-teh-RAH-loh-jist)
A doctor who specializes in diagnosing and treating disorders of the digestive system.

gastroesophageal junction  
The place where the esophagus is connected to the stomach.

gastroesophageal reflux  (GAS-tro-ee-SAH-fuh-JEE-ul REE-flux)
The backward flow of stomach acid contents into the esophagus (the tube that connects the mouth to the stomach). Also called esophageal reflux and gastric reflux.

gastrointestinal  (GAS-troh-in-TES-tih-nul)
Refers to the stomach and intestines. Also called GI.

gastrointestinal carcinoid tumor  (GAS-troh-in-TES-tih-nul KAR-sih-noyd TOO-mer)
An indolent (slow-growing) cancer that forms in cells that make hormones in the lining of the gastrointestinal tract (the stomach and intestines). It usually occurs in the appendix (a small fingerlike pouch of the large intestine), small intestine, or rectum. Having gastrointestinal carcinoid tumor increases the risk of forming other cancers of the digestive system.

gastrointestinal stromal tumor  
A type of tumor that usually begins in cells in the wall of the gastrointestinal tract. It can be benign or malignant. Also called GIST.

gastrointestinal tract  (GAS-troh-in-TES-tih-nul trakt)
The stomach and intestines. The gastrointestinal tract is part of the digestive system, which also includes the salivary glands, mouth, esophagus, liver, pancreas, gallbladder, and rectum.

gastroscope  (GASS-troh-SKOPE)
A thin, tube-like instrument used to examine the inside of the stomach. A gastroscope has a light and a lens for viewing and may have a tool to remove tissue.

gastroscopy  (gas-TROS-koh-pee)
Examination of the inside of the stomach using a gastroscope passed through the mouth and esophagus. A gastroscope is a thin, tube-like instrument with a light and a lens for viewing. It may also have a tool to remove tissue to be checked under a microscope for signs of disease. Also called upper endoscopy.

gastrostomy tube  (gas-TROS-toh-mee ...)
A tube inserted through the wall of the abdomen directly into the stomach. It allows air and fluid to leave the stomach and can be used to give drugs and liquids, including liquid food, to the patient.

GBM  
A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. GBM usually occurs in adults and affects the brain more often than the spinal cord. Also called glioblastoma, glioblastoma multiforme, and grade IV astrocytoma.

GC1008  
A monoclonal antibody being studied in the treatment of kidney cancer, melanoma, and pulmonary fibrosis. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. GC1008 binds to the protein transforming growth factor-beta (TGFß) and may block the growth of cancer cells that make it. Also called anti-TGF-beta monoclonal antibody GC1008.

Gd-DTPA  
A substance used in magnetic resonance imaging (MRI) to help make clear pictures of the brain, spine, heart, soft tissue of joints, and inside bones. Gd-DTPA is being studied in the diagnosis of cancer. It is a type of contrast agent. Also called gadopentetate dimeglumine and Magnevist.

GDC-0449  
A substance being studied in the treatment of cancer. It blocks a type of protein involved in tissue growth and repair and may block the growth of cancer cells. It is a type of Hedgehog signaling pathway antagonist.

gefitinib  (geh-FIH-ty-nib)
A drug that is used to treat certain types of non-small cell lung cancer and is being studied in the treatment of other types of cancer. It is a type of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor. Also called Iressa and ZD1839.

Gelclair  (JEL-klayr)
A gel used to lessen pain from mouth sores caused by chemotherapy or radiation therapy, oral surgery, braces, or disease. Gelclair is being studied in the treatment of pain caused by mouth sores in children receiving cancer treatment. It forms a thin layer over the surface of the mouth and throat to prevent irritation while eating, drinking, and talking. Also called polyvinylpyrrolidone-sodium hyaluronate gel.

geldanamycin analog  
An antineoplastic antibiotic drug that belongs to the family of drugs called ansamycins.

GEM 231  
A drug that may inhibit the growth of malignant tumors.

GEM640  
A substance being studied in the treatment of some types of cancer. GEM640 may block a protein called XIAP so that chemotherapy is able to kill more tumor cells. It is a type of antisense oligonucleotide. Also called AEG35156.

gemcitabine  (jem-SITE-ah-been)
A drug that is used to treat certain types of breast cancer, pancreatic cancer, ovarian cancer, and lung cancer and is being studied in the treatment of other types of cancer. Gemcitabine is a type of antimetabolite. Also called gemcitabine hydrochloride and Gemzar.

gemcitabine hydrochloride  (jem-SITE-ah-been HY-droh-KLOR-ide)
A drug that is used to treat certain types of breast cancer, pancreatic cancer, ovarian cancer, and lung cancer and is being studied in the treatment of other types of cancer. Gemcitabine hydrochloride is a type of antimetabolite. Also called gemcitabine and Gemzar.

gemtuzumab  (gem-TOO-zeh-mab)
A monoclonal antibody combined with a toxic substance that is used to treat certain types of acute myeloid leukemia in older patients and is being studied in the treatment of other types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Gemtuzumab is a type of antibody-drug conjugate. Also called gemtuzumab ozogamicin and Mylotarg.

gemtuzumab ozogamicin  (gem-TOO-zeh-mab oh-zoh-GAM-ih-sin)
A monoclonal antibody combined with a toxic substance that is used to treat certain types of acute myeloid leukemia in older patients and is being studied in the treatment of other types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Gemtuzumab ozogamicin is a type of antibody-drug conjugate. Also called gemtuzumab and Mylotarg.

Gemzar  (JEM-zar)
A drug that is used to treat certain types of breast cancer, pancreatic cancer, ovarian cancer, and lung cancer and is being studied in the treatment of other types of cancer. Gemzar is a type of antimetabolite. Also called gemcitabine and gemcitabine hydrochloride.

Genasense  (JEN-uh-sents)
A substance being studied in the treatment of cancer. It may kill cancer cells by blocking the production of a protein that makes cancer cells live longer and by making them more sensitive to anticancer drugs. It is a type of antisense oligodeoxyribonucleotide. Also called augmerosen, bcl-2 antisense oligodeoxynucleotide G3139, and oblimersen.

gene  
The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

gene deletion  
The total loss or absence of a gene.

gene expression  (JEEN ek-SPREH-shun)
The process by which a gene gets turned on in a cell to make RNA and proteins. Gene expression may be measured by looking at the RNA, or the protein made from the RNA, or what the protein does in a cell.

gene expression profiling  
A research method that measures messenger RNA made from many different genes in various cell types. It is being used as a diagnostic test to help identify subgroups of tumor types, to help predict which patients may respond to treatment, and which patients may be at increased risk for cancer relapse.

gene therapy  (jeen THAYR-uh-pee)
Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body's natural ability to fight the disease or to make the cancer cells more sensitive to other kinds of therapy.

gene transfer  
The insertion of genetic material into a cell.

gene-modified  
Cells that have been altered to contain different genetic material than they originally contained.

general anesthesia  (... A-nes-THEE-zhuh)
Drugs that cause loss of feeling or awareness and put the person to sleep.

generalized anxiety disorder  (JEN-er-uh-lized ang-ZY-eh-tee dis-OR-der)
A condition marked by excessive worry and feelings of fear, dread, and uneasiness that last six months or longer. Other symptoms of generalized anxiety disorder include being restless, being tired or irritable, muscle tension, not being able to concentrate or sleep well, shortness of breath, fast heartbeat, sweating, and dizziness. Also called GAD.

generic  
Official nonbrand names by which medicines are known. Generic names usually refer to the chemical name of the drug.

genetic  (jeh-NEH-tik)
Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.

genetic analysis  
The study of a sample of DNA to look for mutations (changes) that may increase risk of disease or affect the way a person responds to treatment.

genetic counseling  (jeh-NEH-tik KOWN-suh-ling)
A communication process between a specially trained health professional and a person concerned about the genetic risk of disease. The person's family and personal medical history may be discussed, and counseling may lead to genetic testing.

genetic marker  
Alteration in DNA that may indicate an increased risk of developing a specific disease or disorder.

genetic marker of susceptibility  (jeh-NEH-tik… suh-SEP-tih-BIH-lih-tee)
A specific change in a person’s DNA that makes the person more likely to develop certain diseases such as cancer.

genetic predisposition  
An inherited increase in the risk of developing a disease. Also called genetic susceptibility.

genetic profile  (jeh-NEH-tik PROH-file)
Information about specific genes, including variations and gene expression, in an individual or in a certain type of tissue. A genetic profile may be used to help diagnose a disease or learn how the disease may progress or respond to treatment with drugs or radiation.

genetic susceptibility  
An inherited increase in the risk of developing a disease. Also called genetic predisposition.

genetic testing  
Analyzing DNA to look for a genetic alteration that may indicate an increased risk for developing a specific disease or disorder.

genetics  (jeh-NEH-tix)
The study of genes and heredity. Heredity is the passing of genetic information and traits (such as eye color and an increased chance of getting a certain disease) from parents to offspring.

genistein  
An isoflavone found in soy products. Soy isoflavones are being studied to see if they help prevent cancer.

genital  (JEH-nih-tul)
Refers to the genitalia (external and internal sex organs and glands).

genital wart  
A raised growth on the surface of the genitals caused by human papillomavirus (HPV) infection. The HPV in genital warts is very contagious and can be spread by skin-to-skin contact, usually during oral, anal, or genital sex with an infected partner. Also called condyloma.

genitourinary system  (je-nuh-toh-YUR-uh-ner-ee SIS-tem)
The parts of the body that play a role in reproduction, getting rid of waste products in the form of urine, or both.

genome  
The complete genetic material of an organism.

genomic profile  (jeh-NOH-mik PROH-file)
Information about all the genes in an organism, including variations, gene expression, and the way those genes interact with each other and with the environment. A genomic profile may be used to discover why some people get certain diseases while other people do not, or why people respond differently to the same drug.

genomics  (jeh-NOH-miks)
The study of the complete genetic material, including genes and their functions, of an organism.

geranium  (juh-RAY-nee-um)
A type of plant that is native to southern Africa and has white, pink, purple, or red flowers and 3- to 5-lobed leaves. An essential oil that smells like roses is taken from the leaves and used in perfume, in mosquito repellants, and in aromatherapy to treat skin problems and to reduce stress. The scientific name is Pelargonium graveolens. Also called pelargonium.

germ cell  (jurm sel)
A reproductive cell of the body. Germ cells are egg cells in females and sperm cells in males.

germ cell tumor  (jurm sel TOO-mer)
A type of tumor that begins in the cells that give rise to sperm or eggs. Germ cell tumors can occur almost anywhere in the body and can be either benign or malignant.

germ-free  (jurm-free)
Free of bacteria, viruses, and other organisms that can cause infection and disease.

German chamomile  (JER-mun KA-moh-MY-ul)
A plant whose daisy-like flowers are used in tea to calm and relax, improve sleep, and help stomach problems. German chamomile has been studied in the prevention of mucositis (mouth sores) caused by chemotherapy and radiation therapy. It has also been used in some cultures to treat skin conditions, mild infections, and other disorders. The scientific name is Matricaria recutita.

German Commission E  
The German Federal Institute for Drugs and Medical Devices Commission E. A committee made up of scientists, toxicologists, doctors, and pharmacists formed by the German government in 1978 to find out if herbs sold in Germany are safe and effective. The Commission has published information on the uses, side effects, and drug interactions of more than 300 herbs.

germinoma  (jer-mih-NO-ma)
The most common type of germ cell tumor in the brain.

germline DNA  
The DNA in germ cells (egg and sperm cells that join to form an embryo). Germline DNA is the source of DNA for all other cells in the body.

germline mutation  (...myoo-TAY-shun)
A gene change in a body's reproductive cell (egg or sperm) that becomes incorporated into the DNA of every cell in the body of the offspring. Germline mutations are passed on from parents to offspring. Also called hereditary mutation.

Gerota's capsule  (gay-ROH-tuz KAP-sul)
A fibrous envelope of tissue that surrounds the kidney. Also called Gerota's fascia and renal fascia.

Gerota's fascia  (gay-ROH-tuz FA-shuh)
A fibrous envelope of tissue that surrounds the kidney. Also called Gerota's capsule and renal fascia.

Gerson therapy  (GER-sun THAYR-uh-pee)
A diet plan that has been claimed to be a treatment for cancer, migraine, tuberculosis, and other diseases. It is a vegetarian diet that includes eating organic fruits and vegetables and 13 glasses of fresh juice each day. It also includes supplements with iodine, vitamin B-12, potassium, thyroid hormone, liver extract, and pancreatic enzymes. No clinical trial to test Gerson therapy has been reported.

gestational trophoblastic disease  (jeh-STAY-shuh-nul troh-fuh-BLAS-tik dih-ZEEZ)
Any of a group of tumors that develops from trophoblastic cells (cells that help an embryo attach to the uterus and help form the placenta) after fertilization of an egg by a sperm. The two main types of gestational trophoblastic diseases are hydatidiform mole and choriocarcinoma. Also called gestational trophoblastic tumor.

gestational trophoblastic tumor  (jeh-STAY-shuh-nul troh-fuh-BLAS-tik TOO-mer)
Any of a group of tumors that develops from trophoblastic cells (cells that help an embryo attach to the uterus and help form the placenta) after fertilization of an egg by a sperm. The two main types of gestational trophoblastic tumors are hydatidiform mole and choriocarcinoma. Also called gestational trophoblastic disease.

GG745  
A drug used to treat symptoms of an enlarged prostate gland. It is being studied in the treatment of male hair loss and prostate cancer. GG745 blocks enzymes the body needs to make male sex hormones. It is a type of 5-alpha reductase inhibitor. Also called Avodart and dutasteride.

GI  
Refers to the stomach and intestines. Also called gastrointestinal.

GI14721  
An antitumor drug that belongs to the family of drugs called topoisomerase inhibitors. It is a camptothecin analog.

giant cell fibroblastoma  (JY-unt SEL FY-broh-blas-TOH-muh)
A rare type of soft tissue tumor marked by painless nodules in the dermis (the inner layer of the two main layers of tissue that make up the skin) and subcutaneous (beneath the skin) tissue. These tumors may come back after surgery, but they do not spread to other parts of the body. They occur mostly in boys and are related to dermatofibrosarcoma protuberans.

giant hypertrophic gastritis  (JY-unt hy-per-TROH-fik ga-STRY-tis)
A condition marked by inflammation and ulcers (breaks on the skin or on the surface of an organ) of the mucosa (inner lining) of the stomach and by overgrowth of the cells that make up the mucosa. Symptoms include vomiting, diarrhea, and weight loss. Patients with giant hypertrophic gastritis may be at a higher risk of stomach cancer. Also called gastric mucosal hypertrophy and Ménétrier disease.

gigantism  (jy-GAN-tih-zum)
A condition in which the whole body or any of its parts grow much larger than normal.

gimatecan  
A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called topoisomerase inhibitors. Also called ST1481.

ginger  
An herb with a root that has been used in cooking, and by some cultures to treat nausea, vomiting, and certain other medical conditions. It is being studied in the treatment of nausea and vomiting caused by cancer chemotherapy. The scientific name is Zingiber officianale.

gingiva  (JIN-jih-vuh)
The tissue of the upper and lower jaws that surrounds the base of the teeth. Also called gums.

ginkgo  (GING-koh)
A tree native to China. Substances taken from the leaves and seeds have been used in some cultures to treat certain medical problems. Ginkgo has been studied in the prevention and treatment of Alzheimer disease, dementia, certain blood vessel diseases, and memory loss. It may cause bleeding or high blood pressure when used with certain drugs. Also called ginkgo biloba and maidenhair tree.

ginkgo biloba  (GING-koh BY-LOH-buh)
A tree native to China. Substances taken from the leaves and seeds have been used in some cultures to treat certain medical problems. Ginkgo biloba has been studied in the prevention and treatment of Alzheimer disease, dementia, certain blood vessel diseases, and memory loss. It may cause bleeding or high blood pressure when used with certain drugs. Also called ginkgo and maidenhair tree.

ginseng  
An herb with a root that has been used in some cultures to treat certain medical problems. It may have anticancer effects.

GIST  
A type of tumor that usually begins in cells in the wall of the gastrointestinal tract. It can be benign or malignant. Also called gastrointestinal stromal tumor.

gland  
An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.

gland of Lieberkuhn  (... LEE-ber-keen)
Tube-like gland found in the lining of the colon and rectum. Glands of Lieberkuhn renew the lining of the intestine and make mucus. Also called colon crypt.

glans penis  
The rounded, gland-like head of the penis.

glaucoma  (glaw-KOH-muh)
A condition in which there is a build-up of fluid in the eye, which presses on the retina and the optic nerve. The retina is the layer of nerve tissue inside the eye that senses light and sends images along the optic nerve to the brain. Glaucoma can damage the optic nerve and cause loss of vision or blindness.

Gleason score  (GLEE-sun...)
A system of grading prostate cancer tissue based on how it looks under a microscope. Gleason scores range from 2 to 10 and indicate how likely it is that a tumor will spread. A low Gleason score means the cancer tissue is similar to normal prostate tissue and the tumor is less likely to spread; a high Gleason score means the cancer tissue is very different from normal and the tumor is more likely to spread.

Gleevec  (GLEE-vek)
A drug used to treat different types of leukemia and other cancers of the blood, gastrointestinal stromal tumors, skin tumors called dermatofibrosarcoma protuberans, and a rare condition called systemic mastocytosis. It is also being studied in the treatment of other types of cancer. Gleevec blocks the protein made by the bcr/abl oncogene. It is a type of tyrosine kinase inhibitor. Also called imatinib mesylate and STI571.

Gliadel Wafer  
A biodegradable wafer that is used to deliver the anticancer drug carmustine directly into a brain tumor site after the tumor has been removed by surgery. Also called polifeprosan 20 carmustine implant.

glial cell  (GLEE-ul sel)
Any of the cells that hold nerve cells in place and help them work the way they should. The types of glial cells include oligodendrocytes, astrocytes, microglia, and ependymal cells. Also called neuroglia.

glial tumor  
A general term for tumors of the central nervous system, including astrocytomas, ependymal tumors, glioblastoma multiforme, and primitive neuroectodermal tumors.

glioblastoma  (GLEE-oh-blas-TOH-muh)
A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. Glioblastoma usually occurs in adults and affects the brain more often than the spinal cord. Also called GBM, glioblastoma multiforme, and grade IV astrocytoma.

glioblastoma multiforme  (GLEE-oh-blas-TOH-muh MUL-tih-form)
A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. Glioblastoma multiforme usually occurs in adults and affects the brain more often than the spinal cord. Also called GBM, glioblastoma, and grade IV astrocytoma.

glioma  (glee-OH-muh)
A cancer of the brain that begins in glial cells (cells that surround and support nerve cells).

gliosarcoma  (GLEE-oh-sar-KOH-muh)
A type of glioma (cancer of the brain that comes from glial, or supportive, cells).

glossectomy  (glah-SEK-toh-mee)
Surgical removal of all or part of the tongue.

glottis  (GLAH-tis)
The middle part of the larynx; the area where the vocal cords are located.

glucagon  
A hormone produced by the pancreas that increases the level of glucose (sugar) in the blood.

glucagonoma  (GLOO-kuh-guh-NO-ma)
A rare pancreatic tumor that produces a hormone called glucagon. Glucagonomas can produce symptoms similar to diabetes.

glucocorticoid  
A compound that belongs to the family of compounds called corticosteroids (steroids). Glucocorticoids affect metabolism and have anti-inflammatory and immunosuppressive effects. They may be naturally produced (hormones) or synthetic (drugs).

gluconeogenesis  
The process of making glucose (sugar) from its own breakdown products or from the breakdown products of lipids (fats) or proteins. Gluconeogenesis occurs mainly in cells of the liver or kidney.

Glucophage  (GLOO-koh-fayj)
A drug used to treat diabetes mellitus (a condition in which the body cannot control the level of sugar in the blood ). It is also being studied in the treatment of cancer. It decreases the amount of glucose (a type of sugar) released into the bloodstream from the liver and increases the body’s use of the glucose. Glucophage is a type of antidiabetic agent. Also called metformin hydrochloride.

glucose  
A type of sugar; the chief source of energy for living organisms.

glufosfamide  
An anticancer drug that belongs to the family of drugs called alkylating agents.

glutamic acid  (gloo-TA-mik A-sid)
One of twenty amino acids (molecules that join together to form proteins). Glutamic acid may help nerve cells send and receive information from other cells. It is being studied for its ability to decrease or prevent nerve damage caused by anticancer drugs. Also called L-glutamic acid.

glutamine  
An amino acid used in nutrition therapy. It is also being studied for the treatment of diarrhea caused by radiation therapy to the pelvis.

glutathione  
A substance found in plant and animal tissues that has many functions in a cell. These include activating certain enzymes and destroying toxic compounds and chemicals that contain oxygen.

glutathione S-transferase  
A family of enzymes involved in metabolism and in making toxic compounds less harmful to the body.

glycan  (GLY-kan)
A large carbohydrate molecule. It contains many small sugar molecules that are joined chemically. Also called polysaccharide.

glycan analysis  (GLY-kan uh-NA-lih-sis)
A study of the types of carbohydrate (sugar) molecules attached to proteins in cells. Proteins with carbohydrate molecules are called glycoproteins. Glycan analysis is being studied to find out if glycoproteins on cancer cells may be used as biomarkers for cancer.

glycemic index  (gly-SEE-mik …)
A measure of the increase in the level of blood glucose (a type of sugar) caused by eating a specific carbohydrate (food that contains sugar) compared with eating a standard amount of glucose. Foods with a high glycemic index release glucose quickly and cause a rapid rise in blood glucose. Foods with a low glycemic index release glucose slowly into the blood. A relationship between the glycemic index and recurrent colorectal cancer is being studied.

glycinamide ribonucleotide formyltransferase inhibitor  
A drug that blocks DNA synthesis and may prevent tumor growth. It is being studied as a treatment for cancer.

Glycine max  
A product from a plant of Asian origin that produces beans used in many food products. Glycine max contains isoflavones (estrogen-like substances) that are being studied for the prevention of cancer, hot flashes that occur with menopause, and osteoporosis (loss of bone density). Glycine max in the diet may lower cholesterol levels and reduce the risk of heart disease. Also called soy, soya, and soybean.

glycolic acid  (gly-KAH-lik A-sid)
A substance found in some fruits, sugar beets, and sugar cane. It is used in skin care products to reduce wrinkles and soften the skin. It is a type of alpha hydroxyl acid.

glycolysis  
A process in which glucose (sugar) is partially broken down by cells in enzyme reactions that do not need oxygen. Glycolysis is one method that cells use to produce energy. When glycolysis is linked with other enzyme reactions that use oxygen, more complete breakdown of glucose is possible and more energy is produced.

glycopeptide  
A short chain of amino acids (the building blocks of proteins) that has sugar molecules attached to it. Some glycopeptides have been studied for their ability to stimulate the immune system.

glycoprotein  
A protein that has sugar molecules attached to it.

glycoprotein 100  
gp100. A tumor-specific antigen used in the development of cancer vaccines. Also called gp100.

glycosaminoglycan  
A type of long, unbranched polysaccharide molecule. Glycosaminoglycans are major structural components of cartilage and are also found in the cornea of the eye.

GM-CSF  
A substance that helps make more white blood cells, especially granulocytes, macrophages, and cells that become platelets. It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called granulocyte-macrophage colony-stimulating factor and sargramostim.

GM2-KLH vaccine  
A substance used to stimulate the production of antibodies that fight certain cancer cells.

GnRH  
A hormone made by the hypothalamus (part of the brain). GnRH causes the pituitary gland to make luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones are involved in reproduction. Also called gonadotropin-releasing hormone.

goiter  (GOY-ter)
An enlarged thyroid. It may be caused by too little iodine in the diet or by other conditions. Most goiters are not cancer.

gonad  
The part of the reproductive system that produces and releases eggs (ovary) or sperm (testicle/testis).

gonadal dysgenesis  (go-NA-dul dis-JEH-neh-sis)
Abnormal development of a gonad (ovary or testicle). Men with gonadal dysgenesis have a greater risk of developing testicular cancer. Gonadal dysgenesis is usually part of a genetic syndrome.

gonadotropin-releasing hormone  
A hormone made by the hypothalamus (part of the brain). GnRH causes the pituitary gland to make luteinizing hormone (LH) and follicle stimulating hormone (FSH). These hormones are involved in reproduction. Also called GnRH.

gonadotropin-releasing hormone agonist  
A hormone made in the laboratory that has the same effect as the gonadotropin-releasing hormone (GnRH) produced naturally by the body.

gonioscopy  (GOH-nee-OS-koh-pee)
A procedure in which a gonioscope (special lens) is used to look at the front part of the eye between the cornea (the clear layer) and the iris (the colored part of the eye). Gonioscopy checks for blockages in the area where fluid drains out of the eye.

Gonzalez regimen  
An alternative therapy that is being studied as a treatment for pancreatic cancer. It includes a special diet, nutritional supplements, pancreatic enzymes, and coffee enemas.

Gorlin syndrome  
A genetic condition that causes unusual facial features and disorders of the skin, bones, nervous system, eyes, and endocrine glands. People with this syndrome have a higher risk of basal cell carcinoma. Also called basal cell nevus syndrome and nevoid basal cell carcinoma syndrome.

goserelin  (go-SAIR-uh-lin)
A drug that belongs to the family of drugs called gonadotropin-releasing hormone analogs. Goserelin is used to block hormone production in the ovaries or testicles.

gossypol  
An anticancer drug extracted from the cotton plant.

gp100  
A tumor-specific antigen used in the development of cancer vaccines. Also called glycoprotein 100.

gp209-2M  
A peptide (short piece of protein) made from the tumor-specific antigen gp100, and used to make vaccines being studied in the treatment of melanoma.

gp96 heat shock protein-peptide complex vaccine  (… PROH-teen PEP-tide KOM-plex vak-SEEN)
A vaccine made from a patient's tumor cells that may help the body’s immune system find and kill cancer cells. This vaccine is being studied in the treatment of melanoma, kidney cancer, brain tumors, and other types of cancer. It belongs to the family of drugs called biological therapies. Also called gp96 HSP-peptide complex and Oncophage.

gp96 HSP-peptide complex  (… PROH-teen PEP-tide KOM-plex)
A vaccine made from a patient's tumor cells that may help the body’s immune system find and kill cancer cells. This vaccine is being studied in the treatment of melanoma, kidney cancer, brain tumors, and other types of cancer. It belongs to the family of drugs called biological therapies. Also called gp96 heat shock protein-peptide complex vaccine and Oncophage.

GPX-100  
An anticancer drug that belongs to the family of drugs called antitumor antibiotics. It is an anthracycline.

grade  
The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.

grade 1 follicular lymphoma  (... fuh-LIH-kyoo-ler lim-FOH-muh)
An indolent (slow-growing) type of non-Hodgkin lymphoma marked by enlarged lymph nodes and small cells that have cleaved (u-shaped) nuclei.

grade 2 follicular lymphoma  (... fuh-LIH-kyoo-ler lim-FOH-muh)
An indolent (slow-growing) type of non-Hodgkin lymphoma marked by enlarged lymph nodes and a mix of large cells and small cells that have cleaved (u-shaped) nuclei.

grade 3 follicular lymphoma  (... fuh-LIH-kyoo-ler lim-FOH-muh)
A type of non-Hodgkin lymphoma marked by large cells and enlarged lymph nodes. Grade 3 follicular lymphoma is less common, and more aggressive than grades 1 or 2 follicular lymphoma.

grade IV astrocytoma  (... AS-troh-sy-TOH-muh)
A fast-growing type of central nervous system tumor that forms from glial (supportive) tissue of the brain and spinal cord and has cells that look very different from normal cells. Grade IV astrocytoma usually occurs in adults and affects the brain more often than the spinal cord. Also called GBM, glioblastoma, and glioblastoma multiforme.

grading  
A system for classifying cancer cells in terms of how abnormal they appear when examined under a microscope. The objective of a grading system is to provide information about the probable growth rate of the tumor and its tendency to spread. The systems used to grade tumors vary with each type of cancer. Grading plays a role in treatment decisions.

graft  
Healthy skin, bone, or other tissue taken from one part of the body and used to replace diseased or injured tissue removed from another part of the body.

graft-versus-host disease  (... dih-ZEEZ)
A disease caused when cells from a donated stem cell graft attack the normal tissue of the transplant patient. Symptoms include jaundice, skin rash or blisters, a dry mouth, or dry eyes. Also called GVHD.

graft-versus-tumor  
An immune response to a person's tumor cells by immune cells present in a donor's transplanted tissue, such as bone marrow or peripheral blood.

gram  
A unit of weight in the metric system. One gram is equal to one thousandth of a kilogram and is approximately 30-times less than an ounce.

granisetron  (grah-NIH-seh-tron)
The active ingredient in a drug used to treat nausea and vomiting caused by cancer treatment. Granisetron is a type of serotonin receptor antagonist and a type of antiemetic.

granisetron hydrochloride  (grah-NIH-seh-tron HY-droh-KLOR-ide)
A drug used to treat nausea and vomiting caused by cancer treatment. It is a type of serotonin receptor antagonist and a type of antiemetic. Also called Kytril.

granulocyte  (GRAN-yoo-loh-SITE)
A type of white blood cell that fights bacterial infection. Neutrophils, eosinophils, and basophils are granulocytes.

granulocyte colony-stimulating factor  (GRAN-yoo-loh-SITE KAH-luh-nee STIM-yoo-LAY-ting FAK-ter)
A colony-stimulating factor that stimulates the production of neutrophils (a type of white blood cell). It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called filgrastim and G-CSF.

granulocyte-macrophage colony-stimulating factor  (GRAN-yoo-loh-SITE-MA-kruh-FAYJ KAH-luh-nee-STIM-yoo-LAY-ting...)
A substance that helps make more white blood cells, especially granulocytes, macrophages, and cells that become platelets. It is a cytokine that is a type of hematopoietic (blood-forming) agent. Also called GM-CSF and sargramostim.

granulocytic sarcoma  (GRAN-yoo-loh-SIH-tik sar-KOH-muh)
A malignant, green-colored tumor of myeloid cells (a type of immature white blood cell). This tumor is usually associated with myelogenous leukemia. Also called chloroma.

granulocytopenia  (GRAN-yoo-loh-SY-toh-PEE-nee-uh)
A condition in which there is a lower-than-normal number of granulocytes (a type of white blood cell).

granulosa cell tumor  (GRAN-yoo-LOH-suh SEL TOO-mer)
A type of slow-growing, malignant tumor that usually affects the ovary.

gray elm  
The inner bark of this plant has been used in some cultures to treat certain medical problems. It may have antioxidant effects. Also called Indian elm, red elm, slippery elm, sweet elm, Ulmus fulva, and Ulmus rubra.

green tea extract  
A substance that is being studied in the prevention of cancer. It is made from decaffeinated green tea, and contains chemicals called catechins, which are antioxidants. Also called Polyphenon E.

Greene Menopause Index  
A tool used by researchers to study the symptoms of menopause. It is a standard list of 21 questions which women use to rate how much they are bothered by menopause symptoms such as hot flashes, night sweats, rapid heartbeat, and difficulty sleeping.

grief  (GREEF)
The normal response to a major loss, such as the death of a loved one. Grief may also be felt by a person with a serious, long-term illness or with a terminal illness. It may include feelings of great sadness, anger, guilt, and despair. Physical problems, such as not being able to sleep and changes in appetite, may also be part of grief.

grief counseling  (greef KOWN-suh-ling)
The process by which a trained counselor or a support group helps a person work through normal feelings of sorrow after a loss, such as the death of a loved one.

grief therapy  (greef THAYR-uh-pee)
Treatment that helps a person work through a greater than normal reaction to a loss, such as the death of a loved one. This reaction may include behavioral and physical problems, extreme mourning, and being unable to separate emotionally from the person who died. Grief therapy may be individual or group therapy.

groin  
The area where the thigh meets the abdomen.

growth factor  (grohth FAK-ter)
A substance made by the body that functions to regulate cell division and cell survival. Some growth factors are also produced in the laboratory and used in biological therapy.

growth hormone  
A protein made by the pituitary gland that helps control body growth and the use of glucose and fat in the body. Also called somatotropin.

GTI-2040  
A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called antisense oligonucleotides.

guaiac  (GWY-uk)
A substance from a type of tree called Guaiacum that grows in the Caribbean. Guaiac is used in the fecal occult blood test (a test for blood in human stool samples).

gums  
The tissue of the upper and lower jaws that surrounds the base of the teeth. Also called gingiva.

GVHD  
A disease caused when cells from a donated stem cell graft attack the normal tissue of the transplant patient. Symptoms include jaundice, skin rash or blisters, a dry mouth, or dry eyes. Also called graft-versus-host disease.

GW572016  
A drug used with another anticancer drug to treat breast cancer that is HER2 positive and has advanced or metastasized (spread to other parts of the body) after treatment with other drugs. GW572016 is also being studied in the treatment of other types of cancer. It is a type of ErbB-2 and EGFR dual tyrosine kinase inhibitor. Also called lapatinib, lapatinib ditosylate, and Tykerb.

GW786034  
A substance being studied in the treatment of cancer. It is a type of protein tyrosine kinase inhibitor and angiogenesis inhibitor. Also called pazopanib and pazopanib hydrochloride.

gynecologic  (GY-neh-kuh-LAH-jik)
Having to do with the female reproductive tract (including the cervix, endometrium, fallopian tubes, ovaries, uterus, and vagina).

gynecologic cancer  (GY-neh-kuh-LAH-jik KAN-ser)
Cancer of the female reproductive tract, including the cervix, endometrium, fallopian tubes, ovaries, uterus, and vagina.

gynecologic oncologist  (GY-neh-kuh-LAH-jik on-KAH-loh-jist)
A doctor who specializes in treating cancers of the female reproductive organs.

gynecologist  (GY-neh-KAH-loh-jist)
A doctor who specializes in treating diseases of the female reproductive organs.

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Department of Health and Human Services National Institutes of Health USA.gov