Assessment of gastric carcinoma risk associated withHelicobacter pylori may vary depending on the antigen used

BACKGROUND Previous epidemiologic studies produced inconsistent results when examining the relation between Helicobacter pylori infection and the risk of gastric carcinoma by measuring various anti–H. pylori antibodies. This study investigated the increased risk of cancer by examining different antibodies, including the specific anti-CagA antibody and antibodies from two commercially available kits. METHODS An ELISA for the detection of serum anti-CagA was established using a recombinant CagA protein that the authors previously reported. Serum anti-CagA titer was determined for 80 patients with gastric carcinoma and 80 gender- and age-matched controls. Two anti–H. pylori antibodies from the commercially available kits HEL-p (Amrad, Kew Vic, Australia) and HM-CAP (Enteric Product Inc., Westbury, NY) were also evaluated. RESULTS Anti-CagA seropositivity differed significantly between gastric carcinoma patients and controls (92.5% vs. 55.0%; P = 0.0001), showing an odds ratio of 10.4 (95% confidence interval [CI]: 4.23–29.74). The difference was less prominent for the seropositivity of HEL-p (77.5% vs. 58.8%; P = 0.0139; odds ratio: 2.38; 95% CI: 1.20–4.82) and insignificant for that of HM-CAP (65.0% vs. 57.5%; P = 0.4325; odds ratio: 1.30; 95% CI: 0.68–2.49). CONCLUSIONS The current study revealed that the antibody assay system used could be one important factor in the assessment of gastric carcinoma risk for patients with H. pylori. Cancer 2000;88:1530–5. © 2000 American Cancer Society.