title: Regression of low-grade gastric mucosa-associated lymphoid tissue lymphoma after eradication of Helicobacter pylori: possible association with p16 hypermethylation.
abstract: BACKGROUND
  Many reports have stated that the cure of Helicobacter pylori infection can induce a complete remission of low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Although p16 hypermethylation was frequently found in MALT lymphoma, the association between this finding and the remission of MALT lymphoma has not been clarified. We performed a prospective study to evaluate the outcome of patients with low-grade gastric MALT lymphoma and the expression of p16 hypermethylation.
  
  
  METHODS
  We prospectively enrolled 20 patients with H. pylori-positive low-grade gastric MALT lymphoma (stage I E1). After the eradication of H. pylori, the patients were regularly followed-up with endoscopic and histological assessment. The methylation-specific polymerase chain reaction (PCR) (MSP) method was used for the serial detection of p16 hypermethylation.
  
  
  RESULTS
  Eighteen patients (90%) achieved complete remission, with a median duration of 15.7 months. The initial detection rate of p16 hypermethylation was 58% (7 of the 12 patients in whom p16 hypermethylation was evaluated successfully). In a serial investigation, 3 patients who were followed-up for a median 28 months showed that the p16 hypermethylation had disappeared.
  
  
  CONCLUSIONS
  Complete remission of low-grade gastric MALT lymphoma after the eradication of H. pylori infection can be maintained for more than 1 year. Further studies are warranted to investigate the role of p16 hypermethylation in the pathogenesis of gastric MALT lymphoma.
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Korea.
authors.forename: You Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Joo Sung
authors.initials: JS
authors.lastname: Kim
authors.forename: Hyun Chae
authors.initials: HC
authors.lastname: Jung
authors.forename: Chang Hee
authors.initials: CH
authors.lastname: Lee
authors.forename: Chul Woo
authors.initials: CW
authors.lastname: Kim
authors.forename: In Sung
authors.initials: IS
authors.lastname: Song
authors.forename: Chung Yong
authors.initials: CY
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use; D019175:DNA Methylation; D004359:Drug Therapy, Combination; D005260:Female; D015870:Gene Expression; D019942:Genes, p16; D016481:Helicobacter Infections / Q000150:complications / Q000188:drug therapy*; D016480:Helicobacter pylori; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000188:drug therapy / Q000235:genetics* / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000627:therapeutic use; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D012074:Remission Induction; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000382:microbiology*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole