Imatinib, which was developed to target BCR-ABL, platelet-derived growth factor receptor (PDGFR), and c-Kit, is currently used to treat chronic myeloid leukemia, acute lymphoid leukemia, gastrointestinal stromal tumor (GIST), and hypereosinophilic syndrome [25,26,27,28]. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.