Glossary - Resources: Cancer

Content provided by the Faculty of the Harvard Medical School

Glossary

antioxidant: A substance in food that helps to protect cells against damage from free radicals.

benign tumor: A group of abnormal cells that has grown out of control, sometimes forming a detectable mass. Some benign tumors eventually turn cancerous.

carcinogen: A naturally occurring or human-made substance that damages the genetic material in cells and initiates the development of cancer.

carcinoma: The most common type of cancer; it develops in the epithelial tissues that line the surfaces of organs and glands.

carcinoma in situ: A carcinoma in its earliest stage of development before it has spread beyond its original site.

colonoscopy: A screening test for colon cancer in which a thin, flexible tube is inserted into the colon to detect any polyps.

free radicals: Highly reactive molecules that can damage cells, leaving them more vulnerable to other changes leading to cancer.

gene: An individual blueprint, constructed from strands of DNA, that contains information necessary to produce a particular protein.

hormone: Produced by the endocrine glands, hormones encourage or inhibit cell growth.

hyperplasia: Overproduction of normal cells, leading to the enlargement of an organ or other tissue in the body.

immune system: The collective name for a group of cells that defend the body against infections and protect against disease, including cancer. If the immune system is suppressed with medication or damaged, the risk of cancer increases.

mammogram: A form of x-ray of the breast that can identify tissue abnormalities, including cancerous growths. Mammograms can detect breast cancer as much as two years before a lump can be felt.

metastasis: The spread of cancer cells from the point of origin to other parts of the body.

oncogenes: Genes that, once activated, can initiate the process of cancer.

Pap test: Named for George Papanicolaou, the physician who developed it, this test detects cervical cancer as well as the precancerous cells that might precede it.

phytochemicals: Substances in plants that help protect against cancer by boosting the body's own defenses or by helping counter the damaging effects of carcinogens and free radicals.

polyp: A tiny, benign growth in the colon that sometimes develops into cancer. Polyps can be surgically removed to prevent cancer.

PSA test: A test that measures levels of the prostate-specific antigen (PSA), a protein that in high levels may indicate the presence of cancer.

radiation: Waves or particles of energy, some of which are capable of penetrating cell walls and causing genetic damage that, in turn, can lead to cancer.

risk factor: A naturally occurring condition or a substance in the environment that increases a person's chances of developing a disease.

sigmoidoscopy: A screening test for colon cancer, in which a thin tube is inserted into the lower part of the colon to detect any polyps.

tumor: A growth of abnormal cells that can be either benign or cancerous (malignant).

tumor suppressor genes: Genes that can prevent or suppress the development of cancer cells.

ultraviolet radiation: A type of radiation found in sunlight that can penetrate the skin and damage cells.

Last updated:	May 01, 2008