Findings shed light on chemotherapy-induced leukemia

New research suggests that although use of the highly successful chemotherapeutic agents topoisomerase II inhibitors are associated with the development of leukemia, the agents do not directly cause leukemia and, therefore, there may be ways to intervene to prevent this rare complication.

“There are two competing theories of how these therapy-induced leukemias arise,” senior author Dr. Andrew Vaughn, from the UC Davis Cancer Center in Sacramento, said in a statement. “One is that the topoisomerase II inhibitor drugs, in combination with the topoisomerase II enzyme they target, induce random genetic changes that lead to leukemia onset. The other is that another, potentially correctable process is at work.”In the new study, reported in the November 22nd issue of Leukemia, the researchers show that, in fact, the latter theory seems to apply. Specifically, rearrangement of a gene called MLL appears to be involved and if cells harboring this mutation fail to undergo apoptosis then leukemia can develop. Moreover, this rearrangement is independent of the topoisomerase II enzyme.The authors believe that leukemia could be averted with treatments that goad the cells with the MLL mutation into completing apoptosis. (Source: Leukemia 2005;19:2289-2295: Reuters Health: Oncolink: December 2005.)