The Evolving Epidemiology ofHelicobacter pyloriInfection and Gastric Cancer

Abstract

The relationship betweenHelicobacter pyloriinfection and the risk of gastric cancer has been well established in the last decade. Four metaanalyses have found that the infection increases the risk of noncardia gastric cancer by 2- to 6-fold compared with noninfected control populations. However, the role ofcagAstrains ofH pyloriin relation to gastric cancer has not been evaluated systematically. We undertook a meta-analysis of epidemiological studies examining the relationship between infection withcagA-positive strains ofH pyloriand the risk of gastric cancer, and found that patients who are seropositive forcagAstrains ofH pyloriare at an increased risk for developing noncardia gastric cancer compared with those withH pyloriinfection alone. Therefore, searching forcagA-positive strains ofH pylorimay help identify populations at a greater risk for developing gastric cancer.