Helicobacter pylori-associated gastric MALT lymphoma: pathogenesis, diagnosis, and contemporary management

Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent extranodal B-cell lymphoma that arises in close association with chronic Helicobacter pylori (H. pylori) infection and represents a unique paradigm of infection-driven oncogenesis. Persistent H. pylori colonization induces organized lymphoid tissue within the normally lymphoid-poor gastric mucosa, promoting sustained antigen-dependent T-cell-mediated B-cell proliferation and eventual clonal transformation. In contrast to many other lymphoid malignancies, early-stage gastric MALT lymphoma often regresses following microbial eradication, highlighting the central role of antigenic stimulation in disease pathogenesis. This review provides a contemporary overview of H. pylori-associated gastric MALT lymphoma, integrating epidemiology, molecular and immunologic mechanisms of lymphomagenesis, diagnostic evaluation, and modern management strategies. This review gives particular attention to molecular determinants of treatment response, including the t(11;18)(q21;q21)/API2-MALT1 translocation and other NF-κB-activating alterations that promote antigen-independent growth and resistance to eradication therapy. Current therapeutic approaches are reviewed, including antibiotic eradication regimens, radiotherapy, immunotherapy, and systemic treatment strategies for refractory or disseminated disease. By integrating mechanistic insights with clinical practice, this review highlights a precision-based framework for the diagnosis, risk stratification, and management of gastric MALT lymphoma in the modern era.