CAGA SEROPOSITIVITY ASSOCIATED WITH DEVELOPMENT OF GASTRIC-CANCER IN A JAPANESE POPULATION

Background/aims-Infection with Helicobacter pylori strains possessing the cagA gene is associated with increased risk of gastric cancer of t he intestinal type. The aims of this study were to investigate whether CagA seropositivity is associated with increasing risk of gastric can cer in a Japanese population that has a much higher incidence of gastr ic cancer than western populations. Methods-Eighty one gastric cancer patients and 81 sex and age matched endoscopically evaluated controls were studied. Histologically, 62 cancers were of the intestinal type a nd 76 were early gastric cancer. Serum CagA IgG antibodies were assaye d by enzyme linked immunosorbent assay (ELISA) using purified recombin ant CagA protein as antigen. Polymerase chain reaction (PCR) analysis for cagA in H pylori isolates (n = 80) showed that the CagA ELISA had a sensitivity of 83.3% (controls) and 72.5% (cancers). Results-CagA se ropositivity was 60% (49 of 81) in cancer patients and 44% (36 of 81) in controls. The odds ratio for the risk of cancer if CagA seropositiv e was 1.93 (95% confidence interval (CI) 1.01 to 3.68; p < 0.05). In t he 57 H pylori positive cancer patients and their matched H pylori pos itive controls, the odds ratio for the risk of cancer if CagA seroposi tive was 2.2 (95% CI 1.04 to 4.65; p < 0.05). Conclusions-These result s suggest that CagA seropositivity is associated with increased risk o f gastric cancer in Japanese populations.