A cancer arising from epithelium of large bowel is called colorectal cancer. Histologically it can be divided into 2 types: squamous carcinomas or adenocarcinomas. Most of the cancers are adenocarcinomas. Risk factors for developing colon cancers include: 1) age 2) male gender 3) higher with positive family history 4) previous history may lead to recurrence 5) polyps (villous/ tubulovillous) 6) Inflammatory bowel disease such as Crohn's disease 7) immunosuppression 8) diabetes 9) smoking 10) obesity 11) processed meat and 12) alcohol intake.