Abstract
BackgroundThe association of ABO blood groups with gastric cancer risk was proposed decades ago, but the results have been inconsistent.MethodsWe used two single nucleotide polymorphisms to determine ABO genotype in 4932 gastric cancer cases and 6158 controls of Chinese descent, and evaluated the associations of ABO blood groups and genotypes with risk of gastric cancer using multivariable logistic regression models. We also systematically reviewed published literature and performed a meta-analysis of all relevant studies.ResultsIn the case-control study, compared with blood group O, both blood group A and AB were associated with increased gastric cancer risk (for group A, odds ratio (OR) = 1.13, 95% confidence interval (CI): 1.02–1.24; for group AB, OR = 1.18, 95% CI: 1.02–1.36, respectively). Analyses of ABO genotypes revealed associations of AO and AB with risk of gastric cancer compared with OO genotype. Consistent with the case-control study, meta-analysis of 40 studies including 33,613 cases and 2,431,327 controls demonstrated that blood group A (OR = 1.19, 95% CI: 1.13–1.25) and AB (OR = 1.09, 95% CI: 1.03–1.16) were associated with increased risk of gastric cancer.ConclusionsOur analyses validated the association of blood group A with risk of gastric cancer, and suggested that blood group AB was also associated with gastric cancer risk. Functional investigations are warranted to elucidate the exact mechanism of ABO blood groups in gastric carcinogenesis.
Highlights
The association of ABO blood groups with gastric cancer risk was proposed decades ago, but the results have been inconsistent
Study participants Data were derived from three cohorts: Cohort I, the Nanjing/Beijing genome-wide association study (GWAS); Cohort II, the United States National Cancer Institute (NCI) GWAS, and Cohort III, a case-control study conducted in Jiangsu and Ningxia provinces
No apparent deviations from Hardy-Weinberg equilibrium (HWE) in controls were observed for rs8176746 (P = 0.316) and rs687289 (P = 0.410), and no statistically significant associations were observed for rs8176746 or rs687289 with gastric cancer risk under the additive, recessive, dominant or co-dominant models
Summary
The association of ABO blood groups with gastric cancer risk was proposed decades ago, but the results have been inconsistent. Gastric cancer is the fifth most frequently diagnosed cancer and the third leading cause of cancer death worldwide, with estimated 1,033,701 new cases and 782,685 deaths in 2018 [1]. In China, gastric cancer is the second most common cancer type, with about 6,791,000 new cases in 2015 [2]. The ABO blood group system was discovered by Karl Landsteiner in 1900 [7], and it is by far the most important in human blood transfusions. The role of ABO blood types in gastric cancer was initially suggested in more than 60 year ago, with the clinical observation that patients with gastric cancer were more likely to have blood group A than controls [8].
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