Numerous genes implicated in apoptotic induction were found to be repressed or mutated in CML cells such as the tumor suppressor gene p53 [131], the pro-apoptotic members BIM [104] and BAD [132] or members of the anti-apoptotic BCL2 family [132,133,134,135] like BCL2, Bcl-xL and MCL1. BCR-ABL is a potent cell death inhibitor and was demonstrated to promote CML progression by preventing formation of the caspase-9 apoptosome [136]. Here, CASP9 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.