Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

• Published in: World journal of gastroenterology : WJG Vol. 20; no. 3; pp. 684 - 698
• Main Authors: Pereira, Marta-Isabel, Medeiros, José Augusto
• Format: Journal Article
• Language: English
• Published: United States Baishideng Publishing Group Co., Limited 21.01.2014
• Subjects: Gastric Mucosa - immunology; Gastric Mucosa - microbiology; Helicobacter Infections - epidemiology; Helicobacter Infections - immunology; Helicobacter Infections - microbiology; Helicobacter Infections - therapy; Helicobacter pylori - immunology; Helicobacter pylori - pathogenicity; Humans; Immunity, Mucosal; lymphoid; lymphoma; Lymphoma, B-Cell, Marginal Zone - epidemiology; Lymphoma, B-Cell, Marginal Zone - genetics; Lymphoma, B-Cell, Marginal Zone - immunology; Lymphoma, B-Cell, Marginal Zone - microbiology; Lymphoma, B-Cell, Marginal Zone - therapy; Margina; Mucosa-associated; Prognosis; Risk Factors; Stomach Neoplasms - epidemiology; Stomach Neoplasms - genetics; Stomach Neoplasms - immunology; Stomach Neoplasms - microbiology; Stomach Neoplasms - therapy; tissue; Topic Highlight; Eradication therapy; Gastric lymphoma; Mucosa-associated lymphoid tissue lymphoma; Helicobacter pylori; Nuclear factor-kappa B pathway; Marginal zone lymphoma
• DOI: 10.3748/wjg.v20.i3.684
• ISSN: 1007-9327

Mucosa-associated lymphoid tissue(MALT)lymphoma is an indolent extranodal marginal zone B-cell lymphoma,originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus,most notably chronic infection by Helicobacter pylori(H.pylori).This antigenic stimulation initially leads to lymphoid hyperplasia;the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways,with disease progression due to proliferation and resistance to apoptosis,and the emergence of a malignant clone.There are descriptions of MALT lymphomas affecting practically every organ and system,with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors;nevertheless,the digestive system(and predominantly the stomach)is the most frequently involved location,reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens,high mucosal permeability,large extension and intrinsic lymphoid system.While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H.pylori infection,the presence of immortalizing genetic abnormalities,of advanced disease or of eradication-refractoriness requires a more aggressive approach which is,presently,not consensual.The fact that MALT lymphomas are rare neoplasms,with a worldwide incidence of 1-1.5 cases per105population,per year,limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.