title: Levels of circulating polychlorinated biphenyls and mammographic breast density.
abstract: BACKGROUND
  Polychlorinated biphenyls (PCBs) are ubiquitous chemicals found in the environment that accumulate in body fat and exhibit endocrine-disrupting properties. These compounds are therefore suspected of influencing breast cancer risk, but results from studies are inconsistent. To further clarify the role of PCBs in the etiology of breast cancer, the present study aimed to examine the relation of 24 PCB congener levels, which were considered individually and in combinations, with mammographic density, one of the risk factors most strongly associated with breast cancer.
  
  
  METHODS
  Plasma PCB levels were measured by gas chromatography coupled to mass spectrometry in 106 post-menopausal women for whom mammographic density was measured using a computer-assisted method.
  
  
  RESULTS
  Spearman correlation coefficients adjusted for potentially confounding factors (rs) show that while levels of total PCBs do not appear to be correlated with the percentage mammographic density (rs=-0.19, p=0.08), an increase in the plasma levels of congeners nos. 153, 183, 196 and combined Wolff group 3 PCBs is negatively correlated with the percentage mammographic density (rs=-0.24, p=0.03; rs=-0.30, p=0.004; rs=-0.22, p=0.04; and rs=-0.22, p=0.04 respectively).
  
  
  CONCLUSIONS
  Our results suggest that an increase in the plasma levels of some PCB congeners, in particular cytochrome P450 1A1 inducers, is associated with lower mammographic density in post-menopausal women.
authors: Toxicology Laboratory, Quebec National Public Health Institute, 945, avenue Wolfe, Québec, Qc, G1V 5B3 Canada. pierre.ayotte@inspq.qc.ca.
authors: Caroline
authors: C
authors: Diorio
authors: Isabelle
authors: I
authors: Dumas
authors: Torkjel M
authors: TM
authors: Sandanger
authors: Pierre
authors: P
authors: Ayotte
mesh_terms: D000071060:Breast Density; D001943:Breast Neoplasms; D003430:Cross-Sectional Studies; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D042361:Mammary Glands, Human / Q000002:abnormalities*; D008875:Middle Aged; D011078:Polychlorinated Biphenyls / Q000097:blood*; D017698:Postmenopause
chemical_list: D011078:Polychlorinated Biphenyls
keywords: PCB; Polychlorinated biphenyl; breast cancer; mammographic breast density; organochlorine