Anti-topoisomerase drugs as potent inducers of chromosomal aberrations

DNA topoisomerases catalyze topological changes in DNA that are essential f or normal cell cycle progression and therefore they are a preferential targ et for the development of anticancer drugs. Anti-topoisomerase drugs can be divided into two main classes: "cleavable complex" poisons and catalytic i nhibitors. The "cleavable complex" poisons are very effective as anticancer drugs but are also potent inducers of chromosome aberrations so they can c ause secondary malignancies. Catalytic inhibitors are cytotoxic but they do not induce chromosome aberrations. Knowledge about the mechanism of action of topoisomerase inhibitors is important to determine the best anti-topois omerase combinations, with a reduced risk of induction of secondary maligna ncies.