Background: Manganese superoxide dismutase is the primary antioxidant enzyme in the mitochondria and is involved in carcinogenesis. To investigate the association between MnSOD Val(16)Ala polymorphism and risk of advanced gastric lesions, and its effects on chemoprevention, a population-based study was conducted in Linqu, a high-risk area of gastric cancer in China.
Methods: Genotypes were determined by PCR-RFLP analysis in 3,355 subjects with the baseline histopathologic diagnosis in 1994, and 2,758 of these subjects received subsequent three interventions including vitamin supplementation for 7.3 years. Odds ratios (OR) and 95% confidence intervals (CI) were estimated by unconditional logistic regression model.
Results: We found an increased risk of dysplasia in subjects with the Val/Ala+Ala/Ala genotype (OR, 1.31; 95% CI, 1.02-1.68) compared with the Val/Val genotype. Stratified analysis indicated that a significantly elevated risk of intestinal metaplasia (OR, 3.40; 95% CI, 2.64-4.38) or dysplasia (OR, 4.01; 95% CI, 2.79-5.74) was found in subjects carrying the Val/Ala+Ala/Ala genotype and Helicobacter pylori infection, and an interaction between this genotype and a high serum H. pylori IgG titer (>2.94) on the risk of dysplasia was observed (P(interaction) = 0.01). Furthermore, an elevated chance for regression of gastric lesions was observed in subjects with the Val/Ala+Ala/Ala genotype and high IgG titer in an intervention trial with vitamin supplementation (OR, 2.45; 95% CI, 1.37-4.38).
Conclusions: These findings suggest that Val(16)Ala polymorphism may play an important role in development of advanced gastric lesions and modify the effect of vitamin supplementation on the evolution of gastric lesions.
Impact: Val(16)Ala polymorphism is related to gastric cancer development.