cagA-Seropositive Strains ofHelicobacter pyloriIncrease the Risk for Gastric Cancer more than the Presence ofH pyloriAlone

Huang et al have performed a meta-analysis to determine the relationship betweencagA seropositivity (by serology and polymerase chain reaction) and the risk of gastric cancer. An extensive review of the literature identified no previous systematic overviews. The authors identified 16 studies involving 2284 cases and 2770 controls. The overall prevalence of Helicobacter pylori was 77.7% in cases and 63.1% in controls. Tests forcagA were positive in 62.8% of cases and 37.5% of controls. Thus,H pyloriandcagA seropositivity significantly increased the risk for gastric cancer, by 2.28 (95% CI 1.71 to 3.05) and 2.87 (95% CI 1.95 to 4.22), respectively. In patients withH pylori, those who were infected by acagA-positive strain had a slightly higher risk of gastric cancer, with an odds ratio of 1.64 (95% CI 1.21 to 2.24). The authors also found that patients infected withH pyloriwith or withoutcagA seropositivity had an increased risk of noncardia gastric cancer, but not of cancer of the gastric cardia. They concluded thatcagA-positive strains confer a greater risk of gastric cancer than does H pylori infection alone.