Colon cancer. Coloured scanning electron micrograph (SEM) of the mucosa (lining) of the colon (large intestine) of a patient suffering from colonic cancer. Tumour cells (for example pink, centre right) are seen, with healthy, regular mucosal cells (grey, lower left). This patient is suffering from an adenocarcinoma, a malignant tumour derived from glandular structures in the colon wall. Cancer cells divide rapidly and chaotically, and may clump to form tumours that can invade and destroy surrounding tissues. The cancer may be treated by surgical removal of the affected area. Magnification unknown.