title: Polychlorinated biphenyls and breast cancer: A congener-specific meta-analysis.
abstract: The incidence of breast cancer is related to various risk factors, especially that the environmental and lifestyle factors account for major contribution at the rate of 70% to 95% over all. However, there still remains some controversy over the epidemiological evidence regarding the effects of environmental carcinogens on the risk of breast cancer. We conducted a quantitative meta-analysis aiming at full evaluation of the effects of polychlorinated biphenyls (PCBs) on breast cancer in a congener-specific fashion. Four online literature databases were systematically searched before 1st January 2015, for studies stating correlation between PCB congeners and breast cancer. The Newcastle-Ottawa Scale was used to evaluate the quality of the studies that were included in our analysis. Sixteen studies were included in our final meta-analysis after screening based on the priori inclusion criteria. Nine PCB congeners were reported by more than two studies and they were presented in detail. The pooled Odds Ratios (ORs) showed a significant increase in the risk of breast cancer in individuals with higher plasma/fat levels of PCB 99 (OR: 1.36; 95% CI: 1.02 to 1.80), PCB 183 (OR: 1.56; 95% CI: 1.25 to 1.95) and PCB 187 (OR: 1.18; 95% CI: 1.01 to 1.39). Besides, the outcomes did not support a relationship between dioxin-like PCB congeners and the risk of breast cancer. The results of our meta-analysis imply that PCB 99, PCB 183 and PCB 187 would increase the risk of breast cancer. The mechanism of this increased risk may be by the induction of the CYP2B family in cytochrome P450 enzymes.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Leng
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Toxicology, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Xiu-Mei
authors.initials: XM
authors.lastname: Luo
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Department of Biomedical Information, Library, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Yi-Meng
authors.initials: YM
authors.lastname: Li
authors.affiliation: Department of Biomedical Information, Library, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Guo
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Qiao-Yun
authors.initials: QY
authors.lastname: Yang
authors.affiliation: Basic Medical College, Tianjin Medical University, Tianjin 300070, China. Electronic address: lig@tmu.edu.cn.
authors.forename: Guang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin 300070, China. Electronic address: tangnaijun@tmu.edu.cn.
authors.forename: Nai-Jun
authors.initials: NJ
authors.lastname: Tang
mesh_terms: D001943:Breast Neoplasms / Q000139:chemically induced* / Q000453:epidemiology; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity*; D005260:Female; D006801:Humans; D015994:Incidence; D016017:Odds Ratio; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000633:toxicity*; D012307:Risk Factors
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls
keywords: Breast cancer; Congener-specific; Dioxin-like; Meta-analysis; Polychlorinated biphenyls