title: Helicobacter pylori seropositivity and subsite-specific gastric cancer risks in Linxian, China.
abstract: BACKGROUND
  Helicobacter pylori carriage (i.e., persistent exposure to the organism without gastric epithelial cell invasion) is an established risk factor for noncardia gastric cancer. However, its association with the risk of cancer of the gastric cardia is controversial. Consequently, we designed this prospective, nested case-control study to further explore the subsite-specific gastric cancer risks associated with H. pylori seropositivity (a surrogate marker for persistent exposure).
  
  
  METHODS
  A total of 99 patients with gastric cardia cancer, 82 patients with noncardia gastric cancer, and 192 cancer-free subjects were selected from among the participants (n = 29 584) of a nutrition intervention trial previously conducted in Linxian, China. H. pylori seropositivity was determined by assaying for the presence of H. pylori whole cell and CagA antibodies in baseline serum samples from all subjects. Seropositivity was defined as one or both serum assays being positive. Odds ratios (ORs) for subsite-specific gastric cancer were estimated by multivariate logistic regression analyses. All statistical comparisons were two-sided (alpha =.05).
  
  
  RESULTS
  H. pylori seropositivity rates for subjects with gastric cardia cancer, noncardia gastric cancer, and gastric cardia and noncardia cancers combined were 70% (P =.02), 72% (P: =.01), and 71% (P =.003) compared with 56% for cancer-free control subjects. OR estimates for H. pylori seropositivity were 1.87 (95% confidence interval [CI] = 1.10 to 3.17) for gastric cardia cancer, 2.29 (95% CI = 1.26 to 4.14) for noncardia gastric cancer, and 2.04 (95% CI = 1.31 to 3.18) for gastric cardia and noncardia cancers combined.
  
  
  CONCLUSIONS
  H. pylori seropositivity was associated with increased risks for both gastric cardia cancer and noncardia gastric cancer in this well-characterized cohort. Thus, H. pylori carriage may increase the risk of cancer throughout the stomach.
authors.affiliation: Cancer Prevention Studies Branch, Division of Clinical Sciences, National Cancer Institute, Bethesda, MD, USA. limburg.paul@mayo.edu
authors.forename: P
authors.initials: P
authors.lastname: Limburg
authors.forename: Y
authors.initials: Y
authors.lastname: Qiao
authors.forename: S
authors.initials: S
authors.lastname: Mark
authors.forename: G
authors.initials: G
authors.lastname: Wang
authors.forename: G
authors.initials: G
authors.lastname: Perez-Perez
authors.forename: M
authors.initials: M
authors.lastname: Blaser
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: X
authors.initials: X
authors.lastname: Zou
authors.forename: Z
authors.initials: Z
authors.lastname: Dong
authors.forename: P
authors.initials: P
authors.lastname: Taylor
authors.forename: S
authors.initials: S
authors.lastname: Dawsey
mesh_terms: D000230:Adenocarcinoma / Q000382:microbiology* / Q000473:pathology; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000097:blood; D016022:Case-Control Studies; D002681:China; D002986:Clinical Trials as Topic; D005260:Female; D016481:Helicobacter Infections / Q000150:complications* / Q000382:microbiology; D016480:Helicobacter pylori / Q000302:isolation & purification; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012306:Risk; D012307:Risk Factors; D013270:Stomach / Q000382:microbiology*; D013274:Stomach Neoplasms / Q000382:microbiology* / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori