NCI Dictionary of Cancer Terms

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The NCI Dictionary of Cancer Terms features 7,812 terms related to cancer and medicine.

Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.

free radical scavenger
(free RA-dih-kul SKA-ven-jer)
A substance, such as an antioxidant, that helps protect cells from the damage caused by free radicals. Free radicals are unstable molecules that are made during normal cell metabolism (chemical changes that take place in a cell). They can build up in cells and cause damage to other molecules. This damage may increase the risk of cancer and other diseases.