Our data showed that the combination of CPX with CQ or Baf-A1 synergistically enhanced CPX-induced apoptosis and the cleavage of caspase-3, caspase-9 and PARP in K562 cells, indicating that the resistance of leukemia K562 cells to CPX-induced apoptosis was attributed at least in part to the pro-survival autophagic response. This evidence concerns the gene CASP9 and leukemia.