Cell Biology and Cancer
National Cancer Institute Home
skip navigation Main

Getting Started

Teacher's Guide Student Activities About NIH and NCI
glossary | map | contact 
Glossary stack of books
skip glossary links A B C D E F G H I K L M N R S T U X

start of page contentinitiation: Preneoplastic change in the genetic material of cells caused by a chemical carcinogen. Cancer develops when initiated cells are subsequently exposed to the same or another carcinogen.

in situ cancer: Cancer that has remained within the tissue in which it originated.

invasion: As related to cancer, the spread of cancer cells into healthy tissue adjacent to the tumor.

invasive cancer: Cancer that has spread beyond the layer of tissue in which it developed.

keratin: Insoluble protein that is the major constituent of the outer layer of the skin, nails, and hair.

lesion: Area of abnormal tissue change.

leukemia: Cancer of the blood cells.

lifetime risk: Probability that a person, over the course of a lifetime, will develop cancer.

Li-Fraumeni syndrome: Rare family predisposition to multiple cancers, caused by an alteration in the p53 tumor suppressor gene.

lumen: An enclosed space bounded by an epithelial membrane; for example, the lumen of the gut.

malignant: Cancerous; can invade nearby tissue and spread to other parts of the body.

melanin: Skin pigment (substance that gives the skin its color). Dark-skinned people have more melanin than light-skinned people.

melanocyte: Cell in the skin that produces and contains the pigment called melanin.

melanoma: Cancer of the cells that produce pigment in the skin. Melanoma usually begins in a mole.

metastasis: Cancer growth (secondary tumors) that is anatomically separated from the site at which the original cancer developed.

metastasize: To spread from one part of the body to another. When cancer cells metastasize and form secondary tumors, the cells in the metastatic tumor are like those in the original (primary) tumor.

mole: Area on the skin (usually dark in color) that contains a cluster of melanocytes. See also nevus.

monoclonal: Population of cells that was derived by cell division from a single ancestral cell.

morbidity: Disease.

mortality: Death.

mortality rate: Number of deaths per 100,000 persons per year.

mutagen: Any substance that is known to cause mutations.

mutagenesis: Process by which mutations occur.

mutation: Change in the way cells function or develop, caused by an inherited genetic defect or an environmental exposure. Such changes may lead to cancer.

National Cancer Institute (NCI): The largest of the 24 separate institutes, centers, and divisions of the National Institutes of Health. The NCI coordinates the federal government's cancer research program.

National Institutes of Health (NIH): One of eight health agencies of the Public Health Service (the Public Health Service is part of the U.S. Department of Health and Human Services). Composed of 24 separate institutes, centers, and divisions, NIH is the largest biomedical research facility in the world.

necrosis: Cell death.

neoplasia: Abnormal new growth of cells.

neoplasm: New growth of tissue. Can be referred to as benign or malignant.

nevus: Medical term for a spot on the skin, such as a mole. A mole is a cluster of melanocytes that usually appears as a dark spot on the skin.

non-Hodgkin lymphoma: One of the several types of lymphoma (cancer that develops in the lymphocytic system) that are not Hodgkin lymphoma. Hodgkin lymphoma is rare and occurs most often in people aged 15 to 34 and in people over 55. All other lymphomas are grouped together and called non-Hodgkin lymphoma.

back next

Copyright | Credits | Accessibility