No association between AICDA 7888 C/T polymorphism, Helicobacter pylori seropositivity, and the risk of atrophic gastritis and gastric cancer in Japanese

Abstract

Background: The aberrant expression of activation-induced cytidine deaminase (AICDA) was reportedly induced in gastric epithelial cells infected with cytotoxin-associated gene A (cagA)-positive Helicobacter pylori, resulting in the accumulation of alterations in the TP53 tumor suppressor gene in gastric cells. We investigated the association of the AICDA 7888 C/T polymorphism with H. pylori infection and the risk of gastric cancer and atrophic gastritis in Japanese subjects.

Methods: The study subjects were 583 histologically diagnosed gastric cancer patients (cases) and 1637 age- and sex-frequency-matched control outpatients, who visited Aichi Cancer Center Hospital from the years 2001 to 2005. In the controls, serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and atrophic gastritis, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.

Results: H. pylori seropositivity in the controls was not significantly associated with the AICDA 7888 C/T genotypes. Among the H. pylori seropositive control subjects, the age and sex-adjusted ORs of atrophic gastritis were not statistically significant: 0.84 (95% CI, 0.62-1.13) for C/T, 0.82 (95% CI, 0.56-1.21) for T/T, and 0.83 (95% CI, 0.63-1.11) for C/T+T/T, relative to the C/C genotype. The age- and sex-adjusted ORs of gastric cancer relative to atrophic gastritis were also not statistically significant, at 1.17 (95% CI 0.89-1.54), 1.21 (95% CI, 0.85-1.71), and 1.18 (95% CI, 0.91-1.53), respectively. The OR of gastric cancer cases compared with the whole cohort of control subjects was also not significant.

Conclusion: The hypothetical association of the AICDA 7888 C/T polymorphism with the risk of gastric cancer or gastric atrophy was not shown in this study.