Objective: To understand the relationship between AOX1, IRF4 gene methylation status in peripheral blood leukocyte DNA, as well as its interaction with environmental factors, and the risk of breast cancer. Methods: A case-control study was conducted among 401 breast cancer patients and 555 cancer-free controls selected from 2010 to 2014. Methylation sensitive-high resolution melting curve analysis was used to detect the methylation status of AOX1 and IRF4. The multiplication interaction effect between genes' methylation and environmental factors on the risk of breast cancer was analyzed by using unconditional logistic regression, and Excel software was used to analyze the additive interaction effect. Results: Individuals without AOX1 methylation had a 1.37-fold (95%CI: 1.02-1.84) higher breast cancer risk compared to individuals with AOX1 methylation. AOX1 methylation interacted with fungi intake (OR=2.06, 95%CI: 1.12-3.79) and physical activity (OR=2.18, 95%CI: 1.16-4.09) synergistically, on the risk for breast cancer, but no additive interaction effects were observed. Non-methylation of IRF4 could increase the risk for breast cancer, with statistical significance (OR=1.71, 95%CI: 0.99-7.43). Neither multiplication nor additive interactions were observed between IRF4 methylation and environmental factors. Conclusion: Non-methylation of AOX1 and IRF4 were a risk factors for breast cancer.
Aldehyde Oxidase/genetics* ; Breast Neoplasms/genetics* ; Case-Control Studies ; DNA Methylation/genetics* ; Female ; Genetic Predisposition to Disease ; Humans ; Interferon Regulatory Factors/genetics* ; Leukocytes/metabolism*