BCR and chronic myelogenous leukemia, BCR-ABL1 positive: The success of STI-571 (gleevec/imatinib), an inhibitor of the Bcr/Abl fusion oncogene, not only transformed the treatment of chronic myelogenous leukemia (CML) [20], but it also spurred an explosion in the development of additional small molecule inhibitors directed against various other oncodrivers.