Sunitinib, targeting vascular endothelial growth factor receptor 1 (VEGFR1), VEGFR2, and VEGFR3, Fms-like tyrosine kinase-3 (FLT3), and the receptor encoded by the proto-oncogene RET, was approved as second line therapy in 2006 after showing improved time to progression compared with placebo in GIST patients previously treated with imatinib10. This evidence concerns the gene FLT3 and gastrointestinal stromal tumor.