Feng et al. (Feng et al. 2013) reported that inhibiting BIRC5 via YM155 in leukemia HL-60 and U937 cell lines promoted apoptosis, significantly elevating caspase-3 and caspase-8 levels while reducing Mcl-1 expression, with no change in Bcl-2 levels. This evidence concerns the gene MCL1 and leukemia.