Abdomen (AB-do-men): The part of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Abdominal: Having to do with the abdomen, which is the part of the body between the chest and the hips that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Accelerated phase (ak-SEL-er-ay-ted): Refers to chronic myelogenous leukemia that is progressing. The number of immature, abnormal white blood cells in the bone marrow and blood is higher than in the chronic phase, but not as high as in the blast phase.

Acetaminophen: A drug that reduces pain and fever (but not inflammation).

Acetylcysteine: A drug usually used to reduce the thickness of mucus and ease its remits removal. It is also used to reverse the toxicity of high doses of acetaminophen. Also called N-acetylcysteine.

Achlorhydria (a-klor-HY-dree-a): A lack of hydrochloric acid in the digestive juices in the stomach. Hydrochloric acid helps digest food.

Acne: A disorder of the skin marked by inflammation of oil glands and hair glands.

Acoustic (ah-KOOS-tik): Having to do with sound or hearing.

Acridine carboxamide: DACA. A substance that is being studied as an anticancer drug. It belongs to the family of drugs called topoisomerase inhibitors.

Actinic keratosis (ak-TIN-ik ker-a-TOE-sis): A precancerous condition of thick, scaly patches of skin. Also called solar or senile keratosis.

Activate: In biology, to stimulate a cell in a resting state to become active. This causes biochemical anical and functional changes in the activated cell.

Acupressure: The application of pressure or localized massage to specific sites on the body to control symptoms such as pain or nausea. Also used to stop bleeding.

Acitretin: A drug used in cancer prevention that belongs to the family of drugs called retinoids. It is also used in the treatment of psoriasis.

Acupuncture: The technique of inserting thin needles through the skin at specific points on the body to control pain and other symptoms.

Acute: Having the abrupt onset of symptoms and a short course; not chronic.

Acute leukemia: Acute leukemia occurs when a hematopoietic stem cell undergoes malignant transformation into a primitive, undifferentiated cell with abnormal longevity. These lymphocytes (acute lymphocytic leukemia [ALL]) or myeloid cells (acute myelocytic leukemia [AML]) proliferate abnormally, replacing normal marrow tissue and hematopoietic cells and inducing anemia, thrombocytopenia, and granulocytopenia. Because they are blood borne, they can infiltrate various organs and sites, including the liver, spleen, lymph nodes, CNS, kidneys, and gonads.

Acute lymphoblastic leukemia: ALL. A quickly progressing disease in which too many immature white blood cells called lymphoblasts are found in the blood and bone marrow. Also called acute lymphocytic leukemia.

Acute lymphocytic leukic leukemia: ALL. A quickly progressing disease in which too many immature white blood cells called lymphoblasts (immature cells) are found in the blood and bone marrow. Also called acute lymphoblastic leukemia.

Acute myelogenous leukemia: AML. A quickly progressing disease in which too many immature blood-forming cells are found in the blood and bone marrow. Also called acute myeloid leukemia or acute nonlymphocytic leukemia.

Acute myeloid leukemia: AML. A quickly progressing disease in which too many immature blood-forming cells are found in the blood and bone marrow. Also called acute myelogenous leukemia or acute nonlymphocytic leukemia.

Acute nonlymphocytic leukemia: A quickly progressing disease in which too many immature blood- blood-forming cells are found in the blood and bone marrow. Also called acute myeloid leukemia or acute myelogenous leukemia.

Acyclovir: An antiviral agent used to prevent or treat cytomegalovirus and herpes simplex infections that may occur when the body is immunosuppressed.

AD 32: An anticancer drug that belongs to a family of drugs called antitumor antibiotics. It is an anthracycline.

Adenocarcinoma (AD-in-o-kar-sin-O-ma): Cancer that begins in cells that line certain internal organs and that have glandular (secretory) properties.

Adenoid cystic cancer: A rare type of cancer that usually begins in the salivary glands.

Adenoma (ad-in-O-ma): A noncancerous tumour.

Adenopathy (ad-en-OP-a-thee): Large or swollen lymph glands.