title: Gastric mucosa-associated lymphoid tissue lymphomas and Helicobacter pylori infection: a Colombian perspective.
abstract: OBJECTIVE
  To assess the significance of chromosome translocation t(11;18)(q21;q21), B-cell lymphoma 10 (BCL-10) protein and Helicobacter pylori (H. pylori) infection in gastric mucosa-associated lymphoid tissue (MALT) lymphoma in Colombia.
  
  
  METHODS
  Fifty cases of gastric MALT lymphoma and their respective post-treatment follow-up biopsies were examined to assess the presence of the translocation t(11;18)(q21;q21) as identified by fluorescence in situ hybridization; to detect protein expression patterns of BCL10 using immunohistochemistry; and for evaluation of tumor histology to determine the correlation of these factors and resistance to H. pylori eradication.
  
  
  RESULTS
  Infection with H. pylori was confirmed in all cases of gastric MALT lymphoma in association with chronic gastritis. Bacterial eradication led to tumor regression in 66% of cases. The translocation t(11;18)(q21;q21) was not present in any of these cases, nor was there evidence of tumor transformation to diffuse large B-cell lymphoma. Thirty-four percent of the patients showed resistance to tumor regression, and within this group, 7 cases, representing 14% of all those analyzed, were considered to be t(11;18)(q21;q21)-positive gastric MALT lymphomas. Protein expression of BCL10 in the nucleus was associated with the presence of translocation and treatment resistance. Cases that were considered unresponsive to therapy were histologically characterized by the presence of homogeneous tumor cells and a lack of plasmacytic differentiation. Responder cases exhibited higher cellular heterogeneity and a greater frequency of plasma cells.
  
  
  CONCLUSIONS
  Both t(11;18)(q21;q21)-positive MALT lymphoma cases and those with nuclear BCL10 expression are considered resistant to H. pylori eradication. It is suggested that chronic antigenic stimulation is not a dominant event in resistant cases.
authors.affiliation: Institute of Genetics, Universidad Nacional de Colombia, 14490 Bogotá DC, Colombia.
authors.forename: Sally
authors.initials: S
authors.lastname: Yepes
authors.forename: Maria Mercedes
authors.initials: MM
authors.lastname: Torres
authors.forename: Carlos
authors.initials: C
authors.lastname: Saavedra
authors.forename: Rafael
authors.initials: R
authors.lastname: Andrade
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000074018:B-Cell CLL-Lymphoma 10 Protein; D002877:Chromosomes, Human / Q000235:genetics; D003105:Colombia; D016481:Helicobacter Infections / Q000235:genetics / Q000473:pathology; D016480:Helicobacter pylori / Q000472:pathogenicity; D006801:Humans; D016393:Lymphoma, B-Cell / Q000235:genetics* / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics* / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D013274:Stomach Neoplasms / Q000235:genetics* / Q000382:microbiology* / Q000473:pathology / Q000628:therapy; D014178:Translocation, Genetic
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000074018:B-Cell CLL-Lymphoma 10 Protein; C118591:BCL10 protein, human