Level of DNA topoisomerase IIα mRNA predicts the treatment response of relapsed acute leukemic patients

The DNA topoisomerase IIα (Topo IIα) is known as a target enzyme for many chemotherapeutic agents. We investigated the Topo IIα mRNA expression by real-time RT-PCR in 37 paired samples at diagnosis and at relapse of acute leukemic patients in relation to drug sensitivity and clinical outcome. The Topo IIα levels in leukemic blasts at relapse were significantly higher than that at diagnosis, especially in ALL. The increase in the Topo IIα level at relapse was significant in cases which could not achieve a second remission, but not significant in cases which achieved a second remission. These results suggest that the change of Topo IIα expression in leukemic blasts at relapse may predict therapeutic responsiveness.