Many polymorphisms and somatically altered genes in CRC affect the KRAS- (kirsten rat sarcoma viral oncogene homolog), MYC- (cellular myelocytomatosis oncogene), Wnt-, mitogen-activated protein kinase (MAPK)-, or TGF-β/bone morphogenetic protein (BMP)-signaling pathways. The gene discussed is KRAS; the disease is colorectal carcinoma.