Interaction of base excision repair gene polymorphism and estrogen-DNA adducts in breast cancer risk among East Asian women.

Purpose: In East Asia, the incidence of breast cancer has been increasing rapidly, particularly among premenopausal women. An elevated ratio of estrogen-DNA adducts was linked to a higher risk of breast cancer. The present study explored the influence of the interaction between base excision repair (BER) gene polymorphisms and estrogen-DNA adducts on breast cancer risk.

Methods: We conducted a case-control study comprising healthy volunteers and individuals with benign breast disease (control arm, n = 176) and patients with invasive carcinoma or carcinoma in situ (case arm, n = 177). Genotyping for BER-related genes, including SMUG1, OGG1, ERCC5, and APEX1, was performed. A logistic regression model, incorporating interactions between gene polymorphisms, estrogen-DNA adduct ratio, and clinical variables, was used to identify the risk factors for breast cancer.

Results: Univariate analysis indicated marginal associations between breast cancer risk and APEX1 rs1130409 T > G (P = 0.057) and APEX1 rs1760944 T > G (P = 0.065). Multivariate regression analysis revealed significant associations with increased breast cancer risk for APEX1_rs1130409 (GT/GG versus TT) combined with a natural logarithmic value of the estrogen-DNA adduct ratio (estimated OR 1.164, P = 0.023) and premenopausal status with an estrogen-DNA adduct ratio > 2.93 (estimated OR 2.433, P = 0.001).

Conclusion: APEX1_rs1130409 (GT/GG versus TT) polymorphisms, which are related to decreased BER activity, combined with an increased ratio of estrogen-DNA adducts, increase the risk of breast cancer in East Asian women.