Colon cancer. Coloured scanning electron micrograph (SEM) of a freeze-fractured section through the colon wall of a patient suffering from colon cancer. This is the sub-mucosa, the layer that lies beneath the lining of the colon (large intestine). Red blood cells (erythrocytes, red) are seen in the blood vessels that infiltrate the sub-mucosa. This patient is suffering from a colonic adenocarcinoma. This is a malignant tumour that arises from glandular structures in the colon wall. The cancer has caused an increase in the number of blood vessels in the sub-mucosa. It may be treated by surgical removal of the affected area. Magnification unknown.