title: Combined histology and molecular biology for diagnosis of early stage gastric MALT lymphoma.
abstract: OBJECTIVE
  To establish a sequential diagnostic procedure of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and provide evidence for selected optimal cases to be treated in the early stage.
  
  
  METHODS
  Thirty-one cases of gastric lymphoid hyperplasia (GLH) were selected and multiple investigations including histology, protein level, DNA and chromosome levels, combined with clinical follow-up were performed. Histological grade was according to Isaacson's criteria of GLH; CD20, UCHL-1 (CD45RO), anti-kappa (kappa), anti-lambda (lambda) and Ki-67 were used for immunohistochemical staining; semi-nested polymerase chain reaction (PCR) was used to detect IgH gene rearrangement and reverse-transcription PCR (RT-PCR) was used to detect API2-MALT1 fusion of the chromosome translocation t(11;18)(q21;q21). Twenty-nine cases underwent eradication therapy for Helicobacter pylori. Changes in histological grade, endoscopic appearance, expression of Ki-67 and IgH gene rearrangement were compared after eradication treatment.
  
  
  RESULTS
  Of the 31 cases of GLH with predominant chronic gastritis and gastric ulcer most were histological grade 2 and 3. Only one case had lambda light chain restriction and 10 cases had monoclonal IgH gene rearrangement. Expression of Ki-67 and monoclonal IgH gene rearrangement were significantly increased with increased lymphoid hyperplasia (P < 0.05). Two cases had API2-MALT1 fusion. Helicobacter pylori was eradicated in 25 cases and another course of treatment had to be given in 4 cases. All cases were followed up for 1.5-37 months. Of the 27 successful eradication cases, 18 showed complete regression both histologically and endoscopically, 4 had partial regression and 7 were unchanged.
  
  
  CONCLUSIONS
  A sequential diagnostic procedure based on histology, expression of Ki-67 combined with clonality of IgH rearrangement and API2-MALT1 fusion helps to diagnosis of early stage gastric MALT lymphoma and choose the best treatment strategy.
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan Universty, Chengdu, Sichuan Province, China. yizhihui@hotmail.com
authors.forename: Zhi Hui
authors.initials: ZH
authors.lastname: Yi
authors.forename: Qin
authors.initials: Q
authors.lastname: Ouyang
authors.forename: Gan Di
authors.initials: GD
authors.lastname: Li
authors.forename: Dai Yun
authors.initials: DY
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D015321:Gene Rearrangement; D016481:Helicobacter Infections / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008967:Molecular Biology; D009367:Neoplasm Staging; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D004273:DNA, Neoplasm