The significance of Helicobacter pylori in relation to gastric cancer and lymphoma.

The evidence linking Helicobacter pylori and non-cardia gastric adenocarcinoma is accumulating. Patterns of strain specificities and host factors that increase epithelial proliferation and have implications for mutagenic effects are evolving. The decision by the World Health Organization and the International Agency for Research on Cancer to classify H. pylori as a 'definite' carcinogen, however, represents a milestone in the association of H. pylori with gastric carcinogenesis. The importance of H. pylori in gastric lymphoma has been underscored by the finding that H. pylori eradication can induce complete regression in low-grade mucosa-associated lymphoid tissue lymphomas, at least in the early stages of development.