Helicobacter pylori and Gastric Carcinogenesis

Background: Helicobacter pylori causes chronic persistent gastritis in virtually all infected subjects, leading to development of atrophic gastritis, intestinal metaplasia and eventually dysplasia and gastric cancer in a number of infected subjects. Based on the available evidence, an IARC monograph committee classified H. pylori as a class I carcinogen to humans. Prospective studies suggest that infection increases the risk for atrophic gastritis and gastric cancer at least 8-fold. In the presence of infection, the risk for atrophy and cancer seems higher if a subject becomes infected in early childhood, if infection occurs with a cagA positive strain, and if acid output is decreased. Conclusion: H. pylori is a gastric carcinogen. The clinical implications and possible strategies for cancer prevention have to be delineated in the near future.