Antioxidant genes, diabetes and dietary antioxidants in association with risk of pancreatic cancer
R. S Day,
M. M Hassan
2010, 31(4), 607-613. DOI: 10.1093/carcin/bgp310
To test the hypothesis that polymorphic variants of antioxidant genes modify the risk of pancreatic cancer, we examined seven single-nucleotide polymorphisms (SNPs) of genes coding for superoxide dismutase (SOD) 2, glutathione S-transferase alpha 4 (GSTA4), catalase and glutathione peroxidase in 575 patients with pancreatic adenocarcinoma and 648 healthy controls in a case–control study. Information on risk factors was collected by personal interview and dietary information was collected by a self-administered food frequency questionnaire. Genotypes were determined using the Taqman method. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were estimated by unconditional logistic regression. No significant main effect of genotype was observed. A borderline significant interaction between diabetes and SOD2 Ex2+24T>C CT/TT genotype was observed (Pinteraction = 0.051); the AORs (95% CI) were 0.98 (0.73–1.32) for non-diabetics carrying the CT/TT genotype, 1.73 (0.94–3.18) for diabetics carrying the CC genotype and 3.49 (2.22–5.49) for diabetics carrying the CT/TT genotype compared with non-diabetics carrying the CC genotype. Moreover, the SOD2 –1221G>A AA genotype carriers had a significantly increased risk for pancreatic cancer among those with a low dietary vitamin E intake but decreased risk among those with a high vitamin E intake (Pinteraction = 0.002). There was a non-significant interaction between diabetes and GSTA4 Ex5–64G>A genotypes (Pinteraction = 0.078). No significant interaction between genotype with cigarette smoking or vitamin C intake was observed. These data suggest that genetic variations in antioxidant defenses modify the risk of pancreatic cancer in diabetics or individuals with a low dietary vitamin E intake.