Genetic problems in tumours of the gastrointestinal tract.

The role of heredity in the production of gastrointestinal tumours is reviewed. The rare forms showing Mendelian inheritance are described, with special reference to oesophageal cancer and to familial polyposis of the colon. The high risks in these disorders are contrasted with the generally low risks to family members for the common cancers of the digestive tract. The part played by genetic factors in production of the premalignant state is critically discussed, with emphasis on gastric and hepatic cancer. The various experimental genetic approaches to the causation and early detection of cancer are outlined, and it is concluded that both genetic and environmental factors should be considered together when the etiology is being investigated.