Which one of the following drugs is `Topoisomerase 1 inhibitor ?: (A) Doxorubicin, (B) Irinotecan, (C) Etoposide, (D) Vincristine
Answer is B. Ans. is 'b' i.e., Irinotecan Topoisomerase I inhibitors --> camptothecans (Irinotecan, tropotecan). Topoisomerase II inhibitors Anthracyclines (doxorubicin, daunorubicin) and Epipodophyllotoxin (Etoposid, teniposide).