title: Helicobacter pylori and mucosa-associated lymphoid tissue: what's new.
abstract: Low-grade mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach, gastric MALT lymphoma, is associated with Helicobacter pylori infection. The eradication of H pylori using antibiotics is successful in 60% to 80% of affected patients. In contrast to the previous paradigm, we and other investigators have shown that a certain proportion of patients with H pylori-positive early-stage diffuse large B-cell lymphoma (DLBCL) of the stomach with histological evidence of MALT lymphoma, including high-grade transformed gastric MALT lymphoma and gastric DLBCL(MALT), achieved long-term complete pathological remission (pCR) after first-line H pylori eradication therapy, indicating that the loss of H pylori dependence and high-grade transformation are separate events in the progression of gastric lymphoma. In addition, patients with H pylori-positive gastric DLBCL without histological evidence of MALT (gastric pure DLBCL) may also respond to H pylori eradication therapy. A long-term follow-up study showed that patients who achieved pCR remained lymphoma free. Gastric MALT lymphoma is indirectly influenced by H pylori infection through T-cell stimulation, and recent studies have shown that H pylori-triggering chemokines and their receptors, H pylori-associated epigenetic changes, H pylori-regulated miRNA expression, and tumor infiltration by CD4+CD25+ regulatory T cells contribute to lymphomagenesis of gastric MALT lymphoma. Recent studies have also demonstrated that the translocation of CagA into B lymphocytes inhibits apoptosis through p53 accumulation, BAD phosphorylation, and the up-regulation of Bcl-2 and Bcl-XL expression. In gastric MALT lymphoma, CagA may stimulate lymphomagenesis directly, through the regulation of signal transduction, and intracellular CagA is associated with H pylori dependence. These findings represent a substantial paradigm shift compared with the classical theory of H pylori-reactive T cells contributing indirectly to the development of MALT lymphoma. In conclusion, a wide range of H pylori-related gastric lymphomas have been identified. The use of antibiotics as the sole first-line therapy for early-stage gastric pure DLBCL requires validation in a prospective study. The clinical and biological significance of the CagA oncoprotein in the lymphomagenesis of gastric MALT lymphoma warrants further study.
authors: Departments of 1Oncology and.
authors: Sung-Hsin
authors: SH
authors: Kuo
authors: Ann-Lii
authors: AL
authors: Cheng
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D044127:Epigenesis, Genetic / Q000276:immunology; D005753:Gastric Mucosa / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D016481:Helicobacter Infections / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000628:therapy; D016480:Helicobacter pylori / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008221:Lymphoid Tissue / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000628:therapy; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000628:therapy; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013274:Stomach Neoplasms / Q000235:genetics / Q000276:immunology / Q000382:microbiology / Q000401:mortality* / Q000628:therapy; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D051020:bcl-X Protein / Q000235:genetics / Q000276:immunology / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; C494811:BCL2L1 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D051020:bcl-X Protein