ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: The RAS-RAF-dependent mitogen-activated kinase signaling pathway is also a target in CML cells with point mutants of BCR-ABL1 [25], and hydroxyurea kills CML cells with the imatinib-resistant BCR-ABL1 T315I more effectively than cells with BCR-ABL1 [7].