NCI Dictionary of Cancer Terms

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The NCI Dictionary of Cancer Terms features 7,804 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.

topoisomerase II inhibitor
(TOH-poh-i-SAH-meh-rays … in-HIH-bih-ter)
A substance that blocks the activity of the enzyme topoisomerase II, which cuts and repairs tangled strands of DNA. Topoisomerase II is involved in cell division and growth, so blocking activity of this enzyme may kill cancer cells. Some topoisomerase II inhibitors are being used to treat cancer.