Colon cancer. Light micrograph of a section through the colon (large intestine) of a patient with colon cancer. This is an adenocarcinoma, a malignant (cancerous) tumour that arises from glandular tissue in the lining of the colon. Symptoms of colon cancer include rectal bleeding and abdominal pain. Treatment is with surgery to remove the affected area, often combined with chemotherapy. Colon cancer is one of the most common cancers in the Western world. It is a disease of late and middle age. Risk factors include a diet high in animal fat and low in fibre and a sedentary lifestyle. CEA (carcinoembryonic antigen) antibody stain. Magnification: x285 when printed 10 centimetres wide.