Serum polychlorinated biphenyls, cytochrome P-450 1A1 polymorphisms, and risk of breast cancer in Connecticut women

Yawei Zhang, John Piece Wise, Theodore R. Holford, Hong Xie, Peter Boyle, Shelia Hoar Zahm, Jennifer Rusiecki, Kaiyong Zou, Bing Zhang, Yong Zhu, Patricia H. Owens, Tongzhang Zheng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Scopus citations


Recent epidemiologic studies have suggested that genetic polymorphisms in the cytochrome P-450 1A1 gene (CYP1A1) may affect the relation between environmental exposure to polychlorinated biphenyls (PCBs) and breast cancer risk. The authors report results from a case-control study evaluating the potential effect of gene-environment interaction between CYP1A1 and serum PCB levels on breast cancer risk among Caucasian women in Connecticut. The study included 374 case women with histologically confirmed breast cancer and 406 noncancerous controls with information on both serum PCB level and CYP1A1 genotype (1999-2002). Compared with women who had the homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 variant genotype (odds ratio (OR) = 2.1, 95% confidence interval (CI): 1.1, 3.9), especially postmenopausal women (OR = 2.4, 95% CI: 1.1, 5.0). Risks associated with the CYP1A1 m2 variant genotype were highest for all women (OR = 3.6, 95% CI: 1.5, 8.2) and postmenopausal women (OR = 4.3, 95% CI: 1.6, 12.0) with higher serum PCB levels (611-2,600 ng/g). The CYP1A1 ml and m4 genotypes were not associated with breast cancer risk independently or in combination with PCB exposure. In summary, the CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer and may modify the relation between PCB exposure and breast cancer risk.

Original languageEnglish
Pages (from-to)1177-1183
Number of pages7
JournalAmerican Journal of Epidemiology
Issue number12
StatePublished - 15 Dec 2004
Externally publishedYes


  • Breast neoplasms
  • Cytochrome P-450 enzyme system
  • Genetics
  • Polychlorinated biphenyls
  • Polymorphism (genetics)
  • Risk factors
  • Women


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