Carcinogenesis and infection with Helicobacter pylori.

It was accepted several years ago that, in the carcinogenesis process of human cancers, biologic agents, especially the viruses, are playing an etiologic role. This is the case of lymphomas (retroviruses), hepatocarcinoma (hepatic viruses) and cervical carcinoma (papilloma viruses). Helicobacter pylori is the first bacteria recognized as a first class carcinogen for gastric cancer. Nevertheless, comparing with the most validated human carcinogens, the activity of H. pylori is very little studied. As a consequence, at this moment, in its case, explanation of carcinogenesis mechanism is more or less hypothetical.