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NCI Dictionary of Cancer Terms


topoisomerase inhibitor  listen  (TOH-poh-i-SAH-meh-rays in-HIH-bih-ter)

  A substance that blocks topoisomerases (enzymes that break and rejoin DNA strands and are needed for cells to divide and grow). Blocking these enzymes may kill cancer cells. Certain topoisomerase inhibitors are being studied in the treatment of cancer.