MCL1 and acute myeloid leukemia: When sorafenib (25 nM) combined with arsenic trioxide (1 μM), a synergistic apoptosis inducing effect was observed in FLT3-ITD MOLM13 AML cells, which is related to the inactivation of FLT3-ITD (both expression and phosphorylation) and GSK3β, the upregulation of Bax and Bak and the downregulation of Mcl-1.