Bacterial Factors in the Aetiology of Large Bowel Cancer

Abstract

The incidence of large bowel cancer shows a geographical variation, being high in North-West Europe, North America and Australasia and low in much of Africa, South-East Asia and the Andean regions of South America. Initially this distribution appears to favour a major link between the disease and genetic racial factors, since the populations with a high incidence of the disease include all of the Anglo-Saxon countries together with the North and West European peoples and very few others. However, studies of migrants have led to the rejection of this possibility since first generation Japanese migrants to California experience greatly increased incidence of the disease, as do migrants from Eastern Europe to the United States and to Australia. Thus the disease appears to have an environmental rather than a genetic aetiology.