Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma: Updated review of clinical outcomes and the molecular pathogenesis

In most H. pylori-positive patients, gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphomas regress both endoscopically and histopathologically after H. pylori eradication, but no factors that can be predictive of the response to the eradication have been definitively identified, and there is little information on how to determine the optimal observation period before additional treatment can be started. Here, clinical studies dealing with the diagnosis and treatment of gastric MALT lymphomas and H. pylori published during the last 5 years were systematically reviewed, and studies identifying the molecular approaches involved in the pathogenesis were summarized. Most of the clinical studies indicate a favorable effect of H. pylori eradication on the clinical outcome of gastric MALT lymphomas. Some studies suggest the necessity of additional treatment in nonresponders to H. pylori eradication, while others suggest the adoption of a watch-and-wait strategy. The molecular characteristics of MALT lymphomas could play an important role in prognostic prediction and the selection of further therapeutic intervention after the eradication. This updated review of gastric MALT lymphomas illustrates the potential efficacy of H. pylori eradication in tumor remission, but further molecular characterization is necessary to establish the most suitable therapeutic strategy for patients who do not respond to eradication.