Manganese superoxide dismutase (MnSOD Val-9Ala) gene polymorphism and susceptibility to gastric cancer.

BACKGROUND: Oxidative stress caused by the generation of reactive oxygen species plays an important role in human carcinogenesis. Manganese superoxide dismutase (MnSOD) Val-9Ala in the mitochondrial target sequence is the best known polymorphism of this enzyme. The purpose of the current research was to assess the association of MnSOD Val-9Ala genotypes with the risk of gastric cancer. MATERIALS AND METHODS: This case- control study covered 54 gastric cancer patients compared to 100 cancer free subjects as controls. Extraction of DNA was performed on bioptic samples and genotypes were identified with a polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: The frequencies of MnSOD Ala/Ala, Ala/Val and Val/Val genotypes in healthy individuals were 24.3, 66.7 and 9%, respectively. However, in gastric cancer patients, Ala/Ala, Ala/Val and Val/Val were observed in 24.0, 48.0 and 28.0% (p=0.01). In patients the frequency of MnSOD Val allele was higher (52%) compared to that in controls (42%). CONCLUSIONS: The results of this study show a positive association between MnSOD Val-9Ala gene polymorphism and risk of gastric cancer disease in Iranian population.