free radical

Pronunciation: (free RA-dih-kul)

A type of unstable molecule that is made during normal cell metabolism (chemical changes that take place in a cell). Free radicals can build up in cells and cause damage to other molecules, such as DNA, lipids, and proteins. This damage may increase the risk of cancer and other diseases.

Source: NCI Dictionary of Cancer Terms

Date last modified: 2010-11-24