Cancer Dictionary

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hair follicles (FOL-i-kuls): Shafts or openings on the surface of the skin through which hair grows.

hairy cell leukemia: A type of chronic leukemia in which the abnormal white blood cells appear to be covered with tiny hairs when viewed under a microscope.

Helicobacter pylori (HEEL-ih-ko-BAK-ter pye-LOR-ee): Bacteria that cause inflammation and ulcers in the stomach.

hemangiopericytoma: A type of cancer involving blood vessels and soft tissue.

hematogenous: Originating in the blood or spread through the bloodstream.

hematologic malignancies: Cancers of the blood or bone marrow, including leukemia and lymphoma. Also called hematologic cancers.

hematologist (hee-ma-TOL-o-jist): A doctor who specializes in treating diseases of the blood.

hematopoietic growth factors: A group of proteins that cause blood cells to grow and mature.

hematoporphyrin derivative: A drug used in photodynamic therapy that is absorbed by tumor cells. When exposed to light, it becomes active and kills the cancer cells.

heparin: A drug that helps prevent blood clots from forming. It belongs to the family of drugs called anticoagulants (blood thinners).

hepatic: Refers to the liver.

hepatitis (hep-a-TYE-tis): Inflammation of the liver.

hepatitis B: A type of hepatitis that is carried and passed to others through the blood or sexual contact.

hepatoblastoma (HEP-a-toe-blas-TOE-ma): A type of liver tumor that occurs in infants and children.

hepatocellular carcinoma (HEP-a-toe-SEL-yoo-ler kar-sin-O-ma): A type of adenocarcinoma, the most common type of liver tumor.

hepatocyte (HEP-a-toe-site): A liver cell.

hepatoma (hep-a-TOE-ma): A liver tumor.

HER2/neu: Human epidermal growth factor receptor 2. The HER2-neu protein is involved in growth of some cancer cells. Also called c-erbB-2.

HER2/neu gene: The gene that makes the human epidermal growth factor receptor 2. The protein produced is HER2/neu antigen, which is involved in the growth of some cancer cells. Also called c-erbB-2.

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

hereditary nonpolyposis colon cancer: An inherited disorder in which affected individuals have a higher-than-normal chance of developing colon cancer and certain other types of cancer, usually before the age of 60. Also called Lynch syndrome.

herpes virus (HER-peez VYE-rus): A member of the herpes family of viruses.

high-grade lymphomas: Includes large cell, immunoblastic, lymphoblastic and small noncleaved cell lymphomas. These lymphomas grow quickly but have a better response to anticancer drugs than that seen with low-grade lymphomas.

histamine dihydrochloride: A drug being studied for its ability to enhance the effectiveness of IL-2 in treating acute myeloid leukemia.

histology: The study of tissues and cells under a microscope.

HIV: Human immunodeficiency virus, the cause of acquired immunodeficiency syndrome (AIDS).

HIV antibody: A substance produced by certain white blood cells in reaction to contact with HIV, the human immunodeficiency virus.

Hodgkin's disease: A malignant disease of the lymphatic system that is characterized by painless enlargement of lymph nodes, the spleen, or other lymphatic tissue. It is sometimes accompanied by symptoms such as fever, weight loss, fatigue and night sweats.

holmium Ho 166 DOTMP: A drug containing a radioactive isotope that is used in the diagnosis and treatment of cancer.

homeopathic remedies: Small doses of medicines, herbs, or both that are believed to stimulate the immune system.

homoharringtonine: An anticancer drug that belongs to the plant alkaloid family of drugs.

hormonal therapy: Treatment of cancer by removing, blocking, or adding hormones. Also called endocrine therapy.

hormone receptor test: A test to measure the amount of certain proteins, called hormone receptors, in cancer tissue. Hormones can attach to these proteins. A high level of hormone receptors may mean that hormones help the cancer grow.

hormone replacement therapy: HRT. Hormones (estrogen, progesterone, or both) given to postmenopausal women or women who have had their ovaries surgically removed, to replace the estrogen no longer produced by the ovaries.

hormone therapy: Treatment of cancer by removing, blocking, or adding hormones. Also called endocrine therapy.

hormones: Chemicals produced by glands in the body and circulated in the bloodstream. Hormones control the actions of certain cells or organs.

hu14.18-interleukin-2 fusion protein: An anticancer drug in which hu14.18, a monoclonal antibody, is combined with interleukin-2. The monoclonal antibody binds to the cancer cells and delivers IL-2, which stimulates the immune system to destroy the cancer cells.

human papillomavirus (pap-ih-LO-ma VYE-rus): HPV. A virus that causes abnormal tissue growth (warts) and is often associated with some types of cancer.

humidifier (hyoo-MID-ih-fye-er): A machine that puts moisture in the air.

hydration: Combining with water.

hydrocephalus (hye-dro-SEF-uh-lus): The abnormal buildup of cerebrospinal fluid in the ventricles of the brain.

hydrocortisone: A drug used to relieve the symptoms of certain hormone shortages and to suppress an immune response.

hydromorphone: A drug used to relieve pain.

hydroxyurea: An anticancer drug that belongs to the family of drugs called antimetabolites.

hyperbaric oxygen: Oxygen at an atmospheric pressure greater than sea level. Breathing hyperbaric oxygen may enhance the effectiveness of radiation therapy.

hypercalcemia (hye-per-kal-SEE-mee-a): High levels of calcium in the blood.

hyperfractionation: A way of giving radiation therapy in smaller-than-usual doses two or three times a day instead of once a day.

hyperplasia (hye-per-PLAY-zha): An abnormal increase in the number of cells in an organ or tissue.

hypersensitivity: An exaggerated response by the immune system to a drug or other substance.

hyperthermia (hye-per-THER-mee-a): A type of treatment in which body tissue is exposed to high temperatures to damage and kill cancer cells or to make cancer cells more sensitive to the effects of radiation and certain anticancer drugs.

hyperthermic perfusion: A procedure in which a warmed solution containing anticancer drugs is used to bathe, or is passed through the blood vessels of, the tissue or organ containing the tumor.

hyperthyroidism: A condition in which the thyroid gland produces too much thyroid hormone.

hyperuricemia: A buildup of uric acid (a byproduct of metabolism) in the blood; a side effect of some anticancer drugs.

hypervascular: Having a large number of blood vessels.

hypopharynx: The bottom part of the throat. Cancer of the hypopharynx is also called hypopharyngeal cancer.

hypothalamus (hye-po-THAL-uh-mus): The area of the brain that controls body temperature, hunger and thirst.

hysterectomy (hiss-ter-EK-toe-mee): An operation in which the uterus is removed.

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This cancer dictionary is provided by the National Cancer Institute.