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

Objectives: The 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 Methods: A 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.

Results: We 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.

Conclusions: These 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.