[Significance of Helicobacter pylori infection for stomach lymphoma and stomach carcinoma].

The discovery of Helicobacter pylori in 1983 revolutionised pathogenetic hypotheses of almost all gastric diseases and markedly enhanced research especially in the field of malignant tumours of this organ. Based on epidemiological studies indicating an association of H. pylori infection and malignant gastric tumours the WHO classified this bacterium as "class I carcinogen" already in 1994. Although the high prevalence of this germ worldwide is sharply contrasting the low incidence of gastric carcinomas and lymphomas its role as independent risk factor in the carcinogenesis of these tumours today is reasonably evidence-based. Thus, epidemiologists are calculating a reduction of 80% of all MALT-type lymphomas and of about 60% of gastric "non cardia" carcinomas in the scenario of an "H. pylori-free" world. However, complete remission of 80% of early lymphomas of MALT-type confined to mucosa and submucosa, only, after antibiotic eradication of the bacterium is well established in literature and follow-up data are confirming sustained response after years. The strength of impact of an H. pylori infection on gastric carcinogenesis will be figured out by prospective studies on a non infected population in the future.