Secondary Leukemia Associated with the Anti-Cancer Agent, Etoposide, a Topoisomerase II Inhibitor

Etoposide is an anticancer agent, which is successfully and extensively used in treatments for various types of cancers in children and adults. However, due to the increases in survival and overall cure rate of cancer patients, interest has arisen on the potential risk of this agent for therapy-related secondary leukemia. Topoisomerase II inhibitors, including etoposide and teniposide, frequently cause rearrangements involving the mixed lineage leukemia (MLL) gene on chromosome 11q23, which is associated with secondary leukemia. The prognosis is extremely poor for leukemias associated with rearrangements in the MLL gene, including etoposide-related secondary leukemias. It is of great importance to gain precise knowledge of the clinical aspects of these diseases and the mechanism underlying the leukemogenesis induced by this agent to ensure correct assessments of current and future therapy strategies. Here, I will review current knowledge regarding the clinical aspects of etoposide-related secondary leukemia, some probable mechanisms, and strategies for treating etoposide-induced leukemia.