KIT and gastrointestinal stromal tumor: Translational research involving mutant cell lines in gastrointestinal stromal tumors (GIST) and melanoma discovered oncogenic KIT mutations which occurred in exon 11 of the KIT genome [47]. Mutations in exon 11 remove the inherent autoinhibition of the tyrosine kinase activity. This discovery led to the creation of the first-generation tyrosine kinase inhibitors (TKIs): imatinib, sunitinib, and regorafenib.