Seroreactivity to Helicobacter pylori Antigens as a Risk Indicatorof Gastric Cancer

Background: Multiple etiologic factors are suspected to cause gastric cancer, the most important of whichis infection with virulent types of Helicobacter pylori. Materials and
Methods: We have compared 102 gastriccancer patients with 122 non-ulcer, non-cancer dyspeptic patients. Gastric specimens were evaluated for H.pylori infection by tissue-based detection methods. Patient sera underwent antigen-specific ELISA and westernblotting using a Helicoblot 2.1 kit and antibody responses to various H. pylori antigens were assessed.
Results:The absolute majority (97-100%) of both groups were H. pylori seropositive. Multivariate regression analysisdemonstrated serum antibodies to the low molecular weight 35kDa protein to be protective and reduce the riskof gastric cancer by 60% (OR:0.4; 95%CI:0.1-0.9). Conversely, seroreactivity to the 89kDa (VacA) protein wassignificantly higher in gastric cancer patients (OR:2.7; 95%CI:1.0-7.1). There was a highly significant association(p<0.001) between seroreactivity to the 116kDa (CagA) and 89kDa (VacA) proteins, and double positive subjectswere found at nearly five fold (OR:4.9; 95%CI:1.0-24.4) enhanced risk of gastric cancer as compared to doublenegative subjects.
Conclusions: Seroreactivity to H. pylori low (35kDa) and high (116kDa/89kDa) molecularweight antigens were respectively revealed as protective and risk indicators for gastric cancer.