title: Effects of Helicobacter pylori eradication on methylation status of E-cadherin gene in noncancerous stomach.
abstract: OBJECTIVE
  Promoter hypermethylation of E-cadherin plays an important role on gastric cancer development. Whereas E-cadherin methylation was frequently detected in the stomach of Helicobacter pylori-infected individuals, we tested whether eradication of H. pylori alters the methylation status of the noncancerous gastric epithelium.
  
  
  METHODS
  Endoscopic biopsies were taken from the antrum and corpus of H. pylori-infected subjects without gastric cancer. Presence of methylated E-cadherin sequences in the gastric specimens was detected by methylation-specific PCR. Bisulfite DNA sequencing was done to determine the topographical distribution and changes in methylation profiles with H. pylori eradication.
  
  
  RESULTS
  Among the 28 H. pylori-infected subjects (median age, 44.5 years), 15 (53.6%) had E-cadherin methylation detected in stomach at baseline. Discordant methylation patterns between the antrum and corpus were noted in six patients. One year after successful H. pylori eradication, there was a significant reduction in the methylation density of the promoter region and exon 1 of the E-cadherin gene as detected by bisulfite DNA sequencing (P < 0.001).
  
  
  CONCLUSIONS
  Promoter methylation in E-cadherin was frequently detected in the stomach of H. pylori-infected individuals. Eradication of H. pylori might possibly reduce the methylation density in E-cadherin gene and the chance of subsequent neoplastic transformation.
authors.affiliation: Institute of Digestive Disease, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. wkleung@cuhk.edu.hk
authors.forename: Wai K
authors.initials: WK
authors.lastname: Leung
authors.forename: Ellen P S
authors.initials: EP
authors.lastname: Man
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.forename: Minnie Y Y
authors.initials: MY
authors.lastname: Go
authors.forename: Ka-fai
authors.initials: KF
authors.lastname: To
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaoka
authors.forename: Victoria Y Y
authors.initials: VY
authors.lastname: Cheng
authors.forename: Enders K W
authors.initials: EK
authors.lastname: Ng
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
mesh_terms: D000328:Adult; D015820:Cadherins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D019175:DNA Methylation; D005260:Female; D005753:Gastric Mucosa; D016481:Helicobacter Infections / Q000150:complications / Q000188:drug therapy*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011706:Pyloric Antrum / Q000737:chemistry; D013270:Stomach / Q000382:microbiology; D013274:Stomach Neoplasms / Q000209:etiology / Q000382:microbiology / Q000517:prevention & control
chemical_list: D015820:Cadherins