Colon cancer

Most colon cancer is not inherited and is found more frequently in people who have low-fibre, high-fat diets. However, 5-10 per cent of affected people do have an inherited form of the disease. Scientists have identified several genes involved in hereditary colon cancer. These genes normally make proteins that repair damage to other genes, preventing abnormal cell growth. A person who inherits a changed form of any of these genes has a high risk of developing colon cancer, regardless of their diet and lifestyle.

DNA analysis for colon cancer. The lower arrow points to the mutation that has caused colon cancer in the oldest son in this family. None of the other sons has the mutation. Fergus Ryan, National Centre for Medical Genetics, Dublin