KIT and gastrointestinal stromal tumor: Approximately 80% of gastrointestinal stromal tumors (GIST) carry pathogenic activating mutations of proto-Oncogene c-Kit (KIT), while 5% to 10% harbor activating mutations of the platelet-derived growth factor receptor alpha (PDGFRA), both members of the type III class of tyrosine kinase receptors [1,2,3].