The main objective of this study was to examine the cross-sectional relationship between exposure to PCBs or their congeners and breast cancer among US women. There is limited information on the association of specific PCB congener or their combination levels in blood serum with increased breast cancer risk. PCBs are weak estrogens which has been shown to act as endocrine disrupters by increasing or blocking estrogen like activities in animals and humans. We analyzed National Health and Nutrition Examination Survey (NHANES) data from 1999-2004 in the lipid adjusted blood samples of female participants (>20 years of age). Exposure assessment was based on lipid adjusted serum levels of 6 individual PCB congeners (PCB 074, 099, 118, 138, 153, and 180), the sum of dioxin-like PCBs (074 and 118), and the sum of non-dioxin-like PCBs (099 + 138 + 153+187) in conjunction with data obtained from the medical and reproductive health questionnaires. We calculated geometric means to compare PCB concentrations in women's blood samples who also self-reported a breast cancer diagnosis and women who were never diagnosed with cancer. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI) for the association between PCB, their congener or their combinations and breast cancer. We evaluated age, race/ethnicity, age at menarche, body mass index (BMI; kg/m2), and lactation as potential confounders. Our results show a weighted geometric mean levels of 6 PCB congeners to be significantly higher in blood serum among women with breast cancer when compared to the rest of the study population. After adjusting for age, race, BMI, lactation, and age at menarche we found significant association of PCB 138 with breast cancer [odds ratios of 2.88; 95% confidence interval (CI): 1.14-7.30; 2.93, 95% CI: 1.04-8.26; and 3.43, 95% CI: 1.12-10.4] in women with higher body burdens of individual PCB congeners (> 50th percentile, 50th-75th percentile, and ≥75th percentile), respectively. After adjusting for age and race, it was also found that the sum of non-dioxin-like PCBs (074 and 118) in blood serum is significantly associated with breast cancer [OR of 1.14; 95% CI: 1.00-1.29]. In summary, our results suggest a possible link between environmental exposures to PCBs and increased risk of breast cancer among U.S. women.

Citation Format: Marisa Morgan, Alok Deoraj, Deodutta Roy. Association between serum concentrations of polychlorinated biphenyls (PCBs) and increased risk of breast cancer among US women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3433.