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11C topotecan
Pronunciation
Definition 1
A substance being studied in the treatment of certain types of cancer, including ovarian cancer and lung cancer. 11C topotecan is a radioactive form of the anticancer drug topotecan. It builds up in tumor tissues and is detected by positron emission tomography (PET). It may be used to help determine whether treatment with topotecan will work. It is a type of topoisomerase I inhibitor. (NCI Dictionary)
Definition 2
A semisynthetic derivative of camptothecin, a cytotoxic, quinoline-based alkaloid extracted from the Asian tree Camptotheca acuminata radiolabeled with carbon 11 (11C) with antineoplastic and radiotracer properties. During the S phase of the cell cycle, topotecan inhibits topoisomerase I activity by stabilizing the cleavable complex between topoisomerase I and DNA, resulting in DNA breaks that inhibit DNA replication and trigger apoptotic cell death. Quantitation of 11C topotecan accumulated in tumor tissues by positron emission tomography (PET) may help predict responses to topotecan therapy. (NCI Thesaurus)