title: Organochlorines and breast cancer risk by receptor status, tumor size, and grade (Canada).
abstract: OBJECTIVE
  We evaluated the association between organochlorines and breast cancer subtype defined by the tumor characteristics: estrogen receptor status, progesterone receptor status, tumor size, and grade.
  
  
  METHODS
  A case-control study was conducted from 1995 to 1997 in Kingston and Toronto, Canada. Breast adipose tissue, taken from 217 cases and 213 biopsy controls frequency-matched on age, was analysed for 14 polychlorinated biphenyl (PCB) congeners and 10 pesticides.
  
  
  RESULTS
  Adjusting for age, geometric means of several organochlorines differed by estrogen receptor status and tumor grade (p < 0.05). Odds ratios (ORs) for each organochlorine relative to the common control group for breast cancers of differing subtype were compared using polytomous logistic regression. Although the ORs did not differ significantly by subtype, the ORs of PCBs and p, p'-1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) were higher with risk of estrogen receptor-negative breast cancer than estrogen receptor-positive breast cancer. One of the most extreme differences was with DDE, where the OR for the association with risk of estrogen receptor-negative breast cancer was 2.4 (95% confidence interval (CI) 1.0-5.4) in the uppermost tertile relative to the lowest, whereas the corresponding OR for risk of estrogen receptor-positive breast cancer was 1.1 (95% CI 0.6-1.9). PCBs also tended to be more strongly positively associated with risk of larger and higher-grade tumors.
  
  
  CONCLUSIONS
  The association between organochlorines and breast cancer risk did not significantly differ by subtype, but many PCBs were more strongly associated with tumors of poor prognosis.
authors.affiliation: Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada.
authors.forename: C G
authors.initials: CG
authors.lastname: Woolcott
authors.forename: K J
authors.initials: KJ
authors.lastname: Aronson
authors.forename: W M
authors.initials: WM
authors.lastname: Hanna
authors.forename: S K
authors.initials: SK
authors.lastname: SenGupta
authors.forename: D R
authors.initials: DR
authors.lastname: McCready
authors.forename: E E
authors.initials: EE
authors.lastname: Sterns
authors.forename: A B
authors.initials: AB
authors.lastname: Miller
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000328:Adult; D000368:Aged; D001706:Biopsy; D001940:Breast / Q000737:chemistry* / Q000473:pathology*; D001943:Breast Neoplasms / Q000209:etiology* / Q000473:pathology*; D003633:Dichlorodiphenyl Dichloroethylene / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007306:Insecticides / Q000032:analysis; D008875:Middle Aged; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D004785:Environmental Pollutants; D007306:Insecticides; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D003633:Dichlorodiphenyl Dichloroethylene; D011078:Polychlorinated Biphenyls