Since GISTs are frequently driven by the auto-activated, mutant KIT receptor tyrosine kinase gene or by the platelet-derived growth factor receptor alpha (PDGFR-α) [1,2,3], most of the tumors have a durable response to receptor tyrosine kinase inhibitor imatinib mesylate (Gleevec), which is currently considered as an effective drug for first-line therapy for GIST patients [4,5]. The gene discussed is KIT; the disease is gastrointestinal stromal tumor.