KRAS and cancer: The sequence of events with APC/Wnt being the initiating mutation and KRAS a tumor promoting mutation is probably unique to APC and KRAS. To the best of our knowledge, it has not been demonstrated that BRAF mutations can follow APC mutations during the development of conventional adenoma, suggesting that BRAF does not perform strictly equivalent functions as KRAS in the intestinal epithelium to promote transformation and cancer progression.