Interestingly, cellular effects of PHA-739358 and R763/AS703569 in BCR-ABL positive cells are primarily mediated by functional inhibition of Aurora kinase B strongly suggesting that Aurora kinases and not BCR-ABL is the biologically relevant target in TKI-resistant Ph+ leukemia and that Aurora B may be an essential and attractive target in CML cells. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.