These alterations typically are associated with mutations in specific oncogenes or tumor suppressors genes such as adenomatous polyposis coli (APC), Kirsten rat sarcoma virus (KRAS), phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit-α (PIK3CA), b-raf proto-oncogene (BRAF), SMAD family member 4 (SMAD4) or p53 (7), which regulate cell proliferation and cell cycle and play pivotal roles in CRC initiation and progression pathways. The gene discussed is KRAS; the disease is colorectal carcinoma.