Effects of passive smoking on breast cancer risk in pre/post-menopausal women as modified by polymorphisms of PARP1 and ESR1

• Variants in ESR1 and PARP1 modify effect of passive smoking on breast cancer risk.
• The modification direction is opposite among pre- and post-menopausal women.
• It partially explains the different association depending on menopausal status.

ObjectivesThe association between passive smoking and breast cancer risk differs in pre- and post-menopausal women. We aimed to explore the modification effects of PARP1 rs1136410 and ESR1 rs2234693 on the association between passive smoking and breast cancer risk among pre- and post-menopausal women.Design and methodsA case–control study of 839 breast cancer cases and 863 controls was conducted. The gene–environment interactions were tested after adjusting for potential breast cancer risk factors with unconditional logistic regression models.ResultsWe found that the effect of passive smoking was modified by the genotypes in both pre- and post-menopausal women, but in opposite directions. The combination of the TC/CC genotypes of ESR1 rs2234693 and passive smoking significantly increased the risk of breast cancer [OR (95%CI): 2.06 (1.39–3.05)] in pre-menopausal women. A significant association was observed between TT genotype and passive smoking [OR (95%CI): 2.40 (1.27–4.53)] in postmenopausal women. For PARP1 rs1136410, similar differential associations were observed, but the interactions were not significant.ConclusionsThese results imply that the risk of breast cancer from passive smoking may be influenced by genetic factors, and that the association may differ depending on menopausal status.