ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: STI-571 is a small molecule inhibitor of tyrosine kinases, including BCR-Abl, PDGFR and c-kit, and as a result it has been used effectively in patients with chronic myelogenous leukemia, gastrointestinal stromal tumor, and other types of tumors [33-35].