Colon cancer. Coloured Scanning Electron Micro- graph (SEM) of cells from the human colon (large intestine) diseased with cancer. These are cultured malignant tumour cells which have a rough surface due to abnormal cytoplasmic projections. They are also displaying typically chaotic, malignant and uncontrolled cancerous growth. Cancer of the colon is one of the most common cancers, especially in Western countries. Symptoms include blood in the faeces, constipation or diarrhoea, and abdominal pain. Treatment often involves surgery and anti- cancer drugs. Magnification: x1,000 at 6x7cm size.