ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Although imatinib treatment remains the standard of care for Philadelphia chromosome positive CML, increasing imatinib resistance has led to 2nd generation TKIs including dasatinib, nilotinib, and bosutinib, which have shown efficacy in patients who developed BCR-ABL kinase domain mutations while receiving imatinib [29].