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.
Subject(s)
B-Lymphocytes , Cell Survival , Helicobacter , Helicobacter pylori , Immunity, Active , Immunization , Lymphoid Tissue , Lymphoma , Lymphoma, B-Cell, Marginal Zone , Lymphoma, Non-Hodgkin , Molecular Biology , NF-kappa BABSTRACT
Objective To detect chromosome translocation t (11;18)(q21;q21) and expression of BCL10 protein in gastric mucosa associated lymphoid tissue (MALT) lymphoma. Methods We, combining clinical and pathological data, detected API2 MLT fusion by reverse transcriptase polymerase chain reaction (RT PCR)as well as the expressions of BCL10 protein and Ki 67 by immunohistochemistry in cases of gastric MALT lymphoma and follicular gastritis (FG) and analyzed the relationships among them. Results API2 MLT fusion was detected in three cases (2 low grade and 1 low to high grade) out of 14 cases of gastric MALT lymphoma, and no in 8 cases of FG. BCL10 protein was weakly expressed in cytoplasm of B cells of germinal center in lymph follicles of FG; but abundantly in cytoplasm of tumor cells in gastric MALT lymphoma; 42.5% of the latter showed weak expression in nucleus. The expression of Ki 67 was significantly higher in low to high and diffuse large B cell lymphoma cases than in low grade cases( P 0.05), the frequency of nuclear expression of BCL10 increased with the increased expression of Ki 67. Conclusions Both API2 MLT fusion and BCL10 nuclear expression are associated with transformation of gastric MALT lymphoma from LG to HG. RT PCR technique used to detect API2 MLT fusion may be an important tool in identification of t(11;18)(q21;q21).