ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Imatinib mesylate is a tyrosine kinase inhibitor that targets the BCR-ABL protein, c-KIT, and platelet-derived growth factor (PDGF) receptors and is used to treat CML, gastrointestinal stromal tumors, and dermato-fibrosarcoma protuberant.