1. Colorectal cancer develops from adenomatous polyps over many years through the accumulation of genetic mutations in tumor suppressor genes, oncogenes, and DNA repair mechanisms. 2. The major hereditary colorectal cancer syndromes are familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, which are associated with mutations in the APC and DNA MMR genes respectively. 3. Patients with inflammatory bowel disease or a family history of colorectal cancer are at increased risk of developing colorectal cancer.