Aims-In east-Asian countries, while almost all Helicobacter pylori strains possess the cytotokine-associated gene A (CagA) gene, serum CagA antibody is not detected in some infected subjects. We aimed to clarify the association between anti-CagA antibody and gastric cancer in east-Asian countries.Materials & methods-We performed a meta-analysis of case-control studies with age-and sex-matched controls, which provided raw data in east-Asian countries.Results-Ten studies with a total of 4325 patients were identified in the search. Some reports from Japan, Korea and China showed a positive association between the presence of anti-CagA antibody and gastric cancer; however, the results differed in their various backgrounds. The disparate findings appeared to result from the use of different methods or from variations in the antigens used to detect the anti-CagA antibody. CagA seropositivity was associated with an increased risk of developing gastric cancer.
Conclusion
Financial & competing interests disclosureThis report is based on work supported in part by grants from the National Institutes of Health DK62813 and by Ministry of Education, Science, Sports and Culture of Japan; Grant numbers 22390085 and 22659087. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript. . This suggests that serum CagA antibody may be a more useful marker in east-Asian countries than the cagA gene. In this study, we performed a meta-analysis for the relationship between anti-CagA antibody and gastric cancer in east-Asian countries.
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Materials & methodsA literature search was performed using the PubMed database for articles published from January 1990 to March 2010, using the following words: 'CagA', 'enzyme linked immunosorbent assay (ELISA)' or 'serological' or 'seropositive' or 'seropositivity' or 'serum antibody', and 'Japan' or 'China' or 'Korea' or 'east Asia'.
Inclusion criteriaThe following criteria were applied to select fully published case-control studies examining the relationship between anti-CagA antibody of H. pylori and gastric cancer in adult populations: healthy controls were matched with cases by age and sex; the presence of antiCagA antibody was examined by ELISA, immunoblot or both, and all original articles were published in English. H. pylori status was examined serologically by ELISA or immunoblot. Studies were excluded if raw data were not presented, or a histological diagnosis of gastric cancer was not confirmed. When it appeared that the same subjects were presented in multiple reports, the earliest paper was selected. All potentially relevant articles were reviewed by two investigators (Seiji Shiota and Yoshio Yamaoka) independently and disagreement was resolved by discussion.
Data extractionData were extracted from each ...