The drug Imatinib mesylate (Gleevec) is currently used as treatment of chronic myeloid leukemia (CML), Gastrointestinal stromal tumor (GIST) and other malignancies, diseases caused by the Bcr-Abl oncogene, c-Kit mutations or other tyrosine kinase mutations. The gene discussed is KIT; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.