KRAS and colorectal carcinoma: CRC is caused by many high and low penetrant mutations and risk gene modifiers—such as APC, MLH1, MSH2, MSH6, PMS2, AXIN2, POLD, MYH, KRAS, BRAF, NRAS, CTNNB1, TLR2, and FLCN to name a few [16,17,18,19,20,21].