Medical Glossary G

Gallbladder (GAWL-blad-er): The pear-shaped organ that sits below the liver. Bile is stored in the gallbladder.

Gamma knife: Radiation therapy in which high-energy rays are aimed at a tumor from many angles in a single treatment session.

Gardner's Syndrome: A condition that results in the development of polyps and colorectal cancers at a young age. It can also cause benign tumors of the skin, soft connective tissue, and bones.

Gastrectomy (gas-TREK-to-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. It results in a lack of digestive juices.

Gastric Cancer: Cancer of the stomach, also called gastric cancer, is a disease in which cancer (malignant) cells are found in the tissues of the stomach.

Gastroenterologist (GAS-tro-en-ter-OL-o-jist): A doctor who specializes in diagnosing and treating disorders of the digestive system.

Gastrointestinal tract (GAS-tro-in-TES-ti-nul): The part of the digestive tract where the body processes food and eliminates waste. It includes the esophagus, stomach, liver, small and large intestines, and rectum.

Gastroscope (GAS-tro-skope): A thin, lighted instrument to view the inside of the stomach.

Gastroscopy (gas-TROS-ko-pee): An examination of the stomach with a gastroscope, an instrument to view the inside of the stomach.

Gene: The biological or basic unit of heredity found in all cells in the body.

Gene deletion: The total loss or absence of a gene.

Gene therapy: Treatment that alters genes (the basic units of heredity found in all cells in the body). 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 tumor more sensitive to other kinds of therapy.

Genetic: Inherited; having to do with information that is passed from parents to children through DNA in the genes.

Genetic Testing: Specific tests can be done to see if a person has changes in certain genes that are known to be associated with cancer.

Genitourinary system (GEN-i-toe-YOO-rin-air-ee): The parts of the body that play a role in reproduction, in getting rid of waste products in the form of urine, or in both.

Germ cells: The reproductive cells of the body specifically, either egg or sperm cells.

Germ cell tumors: A type of brain tumor that arises from primitive (developing) sex cells, or germ cells.

Germinoma (jer-mih-NO-ma): The most frequent type of germ cell tumor in the brain.

Germline mutation: See hereditary mutation.

Gestational trophoblastic disease: Gestational trophoblastic tumor, a rare cancer in women, is a disease in which cancer (malignant) cells grow in the tissues that are formed following conception (the joining of sperm and egg). Gestational trophoblastic tumors start inside the uterus, the hollow, muscular, pear-shaped organ where a baby grows. This type of cancer occurs in women during the years when they are able to have children.

Gland: An organ that produces and releases one or more substances for use in the body. Some glands produce fluids that affect tissues or organs. Others produce hormones or participate in blood production.

Glioblastoma multiforme (glee-o-blast-TO-ma mul-tih-FOR-may): A type of brain tumor that forms in the nervous (glial) tissue of the brain. They grow very quickly and have cells that look very different from normal cells. Glioblastoma multiforme is also called grade IV astrocytoma.

Glioma (glee-O-ma): A name for brain tumors that begin in the glial cells, or supportive cells, in the brain. "Glia" is the Greek word for glue.

Glottis (GLOT-is): The middle part of the larynx; the area where the vocal cords are located.

Grade: Describes how closely a cancer resembles normal tissue of its same type, and the cancer's probable rate of growth.

Grading: A system for classifying cancer cells in terms of how malignant or aggressive they appear microscopically. The grading of a tumor indicates how quickly cancer cells are likely to spread and plays a role in treatment decisions.

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

Graft-versus-host disease: A reaction of donated bone marrow against a patient's own tissue. Also called GVHD.

Granulocyte (GRAN-yoo-lo-site): A type of white blood cell. Neutrophils, eosinophils, and basophils are granulocytes.

Groin: The area where the thigh meets the hip.

GVHD (graft-versus-host disease): A reaction of donated bone marrow against a patient's own tissue.

Gynecologic oncologists (guy-ne-ko-LA-jik on-KOL-o-jists): Doctors who specialize in treating cancers of the female reproductive organs.

Gynecologist (guy-ne-KOL-o-jist): A doctor who specializes in treating diseases of the female reproductive organs.