NCI Dictionary of Cancer Terms

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The NCI Dictionary of Cancer Terms features 7,861 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.

A hormone that is made by the thyroid gland and contains iodine. T4 increases the rate of chemical reactions in cells and helps control growth and development. T4 can also be made in the laboratory and is used to treat thyroid disorders. Also called L-3,5,5’-tetraiodothyronine, thyroxin, and thyroxine.