Sunitinib is a multitargeted tyrosine kinase inhibitor of VEGFR type 1 and 2, PDGFR∂, and β, c-Kit, FLTF, and RET. In a phase II study, 37.5 mg daily sunitinib was prescribed continuously to 35 patients with FDG-avid, RAI-refractory DTC or medullary thyroid carcinoma (MTC). The gene discussed is KIT; the disease is medullary thyroid gland carcinoma.