title: Seroprevalence of cytotoxin-associated gene A positive Helicobacter pylori strains in Changle, an area with very high prevalence of gastric cancer in south China.
abstract: BACKGROUND
  Helicobacter pylori, especially the CagA-positive strains, are closely associated with peptic ulcers and gastric cancers. We performed a large scale gastric cancer screening project and examined the prevalence of H. pylori and CagA-positive strains in Changle, China, an area with one of the World's highest gastric cancer mortality. We also compared the prevalence with that in Hong Kong which has one-tenth of the gastric cancer mortality of that in Changle.
  
  
  METHODS
  A total of 2424 subjects in Changle and 523 subjects in Hong Kong had endoscopic examination and venesection. Sera were tested for anti-H. pylori antibody and anti-CagA antibody and correlated with endoscopic findings.
  
  
  RESULTS
  In Changle, 80. 9% of the subjects were H. pylori carriers. Out of 551 carriers, 408 (74%) were positive for anti-CagA antibody. A total of 76% and 87% of the asymptomatic and gastric cancer patients were positive for anti-CagA antibody, respectively (P > 0.05). Compared to Hong Kong, there was a significantly (P < 0.0001) higher prevalence of CagA-positive strains in asymptomatic subjects in Changle (76%) than in Hong Kong (28%), but not in peptic ulcers or gastric cancers.
  
  
  CONCLUSIONS
  Subjects in Changle had a high prevalence of H. pylori infection and a high prevalence of the CagA-positive strains. The contrast in the prevalence of CagA-positive strains, in asymptomatic subjects in two areas with differing gastric cancer mortality, supports the pathogenic role of CagA-positive strains in gastric carcinogenesis.
authors.affiliation: Department of Medicine and Pathology, University of Hong Kong, Hong Kong.
authors.forename: B C
authors.initials: BC
authors.lastname: Wong
authors.forename: S K
authors.initials: SK
authors.lastname: Lam
authors.forename: C K
authors.initials: CK
authors.lastname: Ching
authors.forename: W H
authors.initials: WH
authors.lastname: Hu
authors.forename: L Y
authors.initials: LY
authors.lastname: Ong
authors.forename: B W
authors.initials: BW
authors.lastname: Chen
authors.forename: Z
authors.initials: Z
authors.lastname: Gao
authors.forename: J S
authors.initials: JS
authors.lastname: Chen
authors.forename: X W
authors.initials: XW
authors.lastname: Jiang
authors.forename: X H
authors.initials: XH
authors.lastname: Hou
authors.forename: J Y
authors.initials: JY
authors.lastname: Lu
authors.forename: W H
authors.initials: WH
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Ho
authors.forename: S T
authors.initials: ST
authors.lastname: Yuen
authors.forename: K C
authors.initials: KC
authors.lastname: Lai
authors.forename: E
authors.initials: E
authors.lastname: Kwok
authors.forename: W M
authors.initials: WM
authors.lastname: Hui
authors.forename: A
authors.initials: A
authors.lastname: Covacci
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000235:genetics* / Q000276:immunology; D005260:Female; D016481:Helicobacter Infections / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011446:Prospective Studies; D016036:Seroepidemiologic Studies; D013274:Stomach Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori