Patients having mutations in exon 9 of kit gene also may respond to imatinib but with higher doses, whereas patients without mutations in the kit gene do not respond to imatinib.13The Scandinavian Sarcoma Group XVIII trial established a postoperative therapy of 3 years with imatinib in high-risk GISTs.13Sunitinib (tyrosine kinase inhibitor) is used for treatment of imatinib refractory GIST and in patients unable to tolerate imatinib.13Sunitinib targets multiple kinases, including vascular endothelial growth factor receptors, PDGFRA, KIT, and FLt3. This evidence concerns the gene PDGFRA and gastrointestinal stromal tumor.