It is well known that around 30% of colorectal carcinomas or large adenomas present an activating mutation of the K-RAS oncogene [32, 33]; on the other hand, around 10% of CRCs harbour an activating mutation of the BRAF oncogene (V600E) [32]; mutations in either K-RAS or BRAF are common in colorectal tumors but are mutually exclusive, because they encode kinases that belong to the mitogen-activated protein kinase (MAPK) cascade. The gene discussed is KRAS; the disease is adenoma.