Pathogenesis of Gastric MALT Lymphoma

ABSTRACT

Mucosa-associated lymphoid tissue (MALT) lymphoma is a heterogeneous form of a B-cell non-Hodgkin's lymphoma with extranodal location. In the view of molecular biology, there are two types of MALT lymphoma translocation-negative MALT lymphoma and translocation-positive MALT lymphoma. The pathogenesis of translocation-negative MALT lymphoma is driven by an active immune response to Helicobacter pylori infection. Thismost probably underscores the tumor cell survival and proliferation, and thus determines their response to Helicobacter pylorieradication. The oncogenic products of t(1;14) (p22;q32)/CL10-IGH, t(14;18)(q32;21)/IGH-MALT1 and t(11;18)(q21;q21)/API2-MALT1, found in translocation-positive MALT lymphoma, are all potent activators of the NF-kappaB activation pathway. They activate the canonical NF-kappaB activation pathway, and also potentially trigger directly and /r indirectly activation of the non-canonical NF-kappaB pathway. Inactivation of the global NF-kappaB inhibitor A20 also impacts upon multiple signaling pathways leading to NF-kappaB activation and thus potentially exacerbates the effect of stimulation of surface receptors. This review discusses the recent advances in the molecular pathogenesis of MALT lymphoma, and explores how the above genetic abnormalities cooperate with immunological stimulation in the development of lymphoma.