SMAD4 and malignant colon neoplasm: Whole-exome sequencing (WES) of colon cancer revealed mutations in more than 20 genes, including KRAS, PIK3CA, APC, SMAD4, etc. The results of whole-exome sequencing (WES) of jejunal GISTs revealed an NF1 mutation and no KIT or PDGFR gene mutation.