title: Helicobacter pylori and CagA seropositivity and its association with gastric and oesophageal carcinoma.
abstract: OBJECTIVE
  Helicobacter pylori infection is an established risk factor for non-cardia gastric adenocarcinoma. Infection with H. pylori strains harbouring the cagA pathology island may augment this association. H. pylori infection may at the same time reduce the risk for oesophageal carcinoma. However, prospective data on the association between CagA seropositivity and gastric or oesophageal carcinomas are limited. The purpose of this study was to investigate whether CagA seropositivity among H. pylori seropositive subjects is associated with gastric or oesophageal carcinomas.
  
  
  METHODS
  A nested case-control study was performed in the Malmö Preventive Medicine cohort consisting of 32,906 middle-aged subjects. Tumour cases were identified by the Swedish National Cancer Registry. The Western blot method Helicoblot 2.1 was used to detect H. pylori and CagA seropositivity.
  
  
  RESULTS
  Non-cardia gastric adenocarcinoma was associated with H. pylori seropositivity, odds ratio 17.8 (95% CI: 4.2-74.8; 67 cases). The odds ratio for CagA seropositivity among H. pylori seropositive subjects was 9.7 (95% CI: 1.5-infinity). No significant associations were found between cardia gastric adenocarcinoma and H. pylori or CagA seropositivity among H. pylori seropositive subjects; odds ratios were 1.5 (95% CI: 0.51-4.8) and 2.7 (95% CI: 0.38-infinity), respectively (24 cases). Oesophageal adenocarcinoma and oesophageal squamous cell carcinoma were not significantly associated with H. pylori seropositivity or with CagA seropositivity among H. pylori seropositive subjects; the odds ratios associated with oesophageal adenocarcinoma were 0.46 (95% CI: 0.07-2.6) and 0.38 (95% CI: 0.02-24), respectively. Corresponding odds ratios for oesophageal squamous cell carcinoma were 0.44 (95% CI: 0.15-1.2; 37 cases) and 2.0 (95% CI: 0.24-infinity), respectively.
  
  
  CONCLUSIONS
  CagA seropositivity among H. pylori seropositive subjects is a risk factor for non-cardia gastric adenocarcinoma.
authors.affiliation: Department of Medicine, Malmö University Hospital, Lund University, Malmö, Sweden. Henrik.Siman@med.lu.se
authors.forename: J Henrik
authors.initials: JH
authors.lastname: Simán
authors.forename: Lars
authors.initials: L
authors.lastname: Engstrand
authors.forename: Göran
authors.initials: G
authors.lastname: Berglund
authors.forename: Arne
authors.initials: A
authors.lastname: Forsgren
authors.forename: Claes-Henrik
authors.initials: CH
authors.lastname: Florén
mesh_terms: D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis*; D001426:Bacterial Proteins / Q000032:analysis*; D016022:Case-Control Studies; D004938:Esophageal Neoplasms / Q000097:blood* / Q000150:complications*; D005260:Female; D016481:Helicobacter Infections / Q000097:blood* / Q000150:complications*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000097:blood* / Q000150:complications*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori