Role of bacteria in human carcinogenesis.

The bacterial hydrolysis of conjugated carcinogens, production of potential carcinogens from amino acid metabolism, formation of N-nitroso-compounds, and production of carcinogens from bile salt metabolism are discussed. The limited evidence implicating these compounds in the causation of bowel, gastric, bladder, biliary tract and cervical cancer is presented. Although there is no example of a proven role for bacteria in the causation of any human cancer, there are many leads currently under investigation. They have exciting implications for prevention.