Chen et al. [37] found that APC and KRAS, which are frequently mutated in colorectal adenocarcinoma, were also commonly altered in colorectal NECs, unlike GEP-NETs and lung NECs [38, 39], suggesting that cell-cycle regulation, Wnt signaling, and MAPK and PI3K signaling are frequently aberrant in colorectal NECs. This evidence concerns the gene KRAS and colorectal adenocarcinoma.