One of these chemotherapeutic drugs, Imatinib Mesylate, also known as Gleevec or ST1-571, is a tyrosine-kinase inhibitor that targets Bcr-Abl protein, c-Kit, and platelet derived growth factor receptor and is used as a first-line treatment for chronic myeloid leukemia (CML) and gastrointestinal stromal tumor (GIST) [2, 3]. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.