KIT and gastrointestinal stromal tumor: Exhaustive exome sequencing analysis revealed no pathogenic mutations in other GIST-related genes, such PDGFRA, BRAF, and neurofibromin 1, and only a nonsynonymous missense variant in exon 18 of KIT. This variant is described in the COSMIC database (COSM133780) in 1 case of malignant melanoma.