Sunitinib is an orally bioavailable multityrosine kinase inhibitor that blocks VEGFR1-3, Flt-3, PDGFR-α, PDGFR-β, c-Kit, CSF-1R, and RET with proven antitumor activity in renal cell carcinoma and imatinib-resistant or -intolerant gastrointestinal stromal tumor (GIST) [4]. The gene discussed is PDGFRB; the disease is gastrointestinal stromal tumor.