Dasatinib, an inhibitor of BCR-ABL and SRC kinases, is a second-generation tyrosine kinase inhibitor approved for the treatment of imatinib-resistant chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL). The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.