Gleevec (imatinib) is a targeted tyrosine kinase inhibitor used to treat several cancers, most notably Philadelphia chromosome-positive Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL). It also treats Gastrointestinal Stromal Tumors (GIST), dermatofibrosarcoma protuberans, and certain myelodysplastic and myeloproliferative diseases by blocking specific cancer-promoting proteins.