9Chen GQ, Zhu J, Shi XG, et al. In vitro studies on cellular and molecular mechanisms of arsenic trioxide (As203) in the treatment of acute promyelocytic leukemia: As203 induces NB4 cell apoptosis with downregulation of Bcl-2 expression and modulation of PML-RARa/PML proteins [ J ]. Blood, 1996,88 (3) :1052-1061.