Other KIT oncogenic mutations, including an exon 13 K642E primary mutation, and the exon 14 T670I “gatekeeper” secondary mutation, were inhibited effectively by both sunitinib and regorafenib.32,33 Very similar GIST inhibition profiles were demonstrated for regorafenib and the structurally-related compound, sorafenib, demonstrating the reproducibility of the models. Here, KIT is linked to gastrointestinal stromal tumor.