BMC Cancer Research article Estrogen and progesterone receptor levels in nonneoplastic breast epithelium of breast cancer cases versus benign breast biopsy controls Christy G Woolcott1, Sandip K SenGupta2, Wedad M Hanna3,4 and Kristan J Aronson*5 BioMed Central Open Access Address: 1Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, 96813, USA, 2Department of Pathology and Molecular Medicine, Queen's University, Kingston, Ontario, K7L 3N6, Canada, 3Department of Pathology, Sunnybrook Health Sciences Centre, Toronto, Ontario, M5S 1B2, Canada, 4Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, M5G 1L5, Canada and 5Department of Community Health and Epidemiology, and Division of Cancer Care and Epidemiology, Cancer Research Institute, Queen's University, Kingston, Ontario, K7L 3N6, Canada Email: Christy G Woolcott - cwoolcott@crch.hawaii.edu; Sandip K SenGupta - sengupts@KGH.KARI.NET; Wedad M Hanna - wedad.hanna@sunnybrook.ca; Kristan J Aronson* - aronson@queensu.ca * Corresponding author Published: 8 May 2008 BMC Cancer 2008, 8:130 doi:10.1186/1471-2407-8-130 This article is available from: http://www.biomedcentral.com/1471-2407/8/130 Received: 27 November 2007 Accepted: 8 May 2008 © 2008 Woolcott et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Previous studies and biological mechanisms of carcinogenesis suggest that the steroid receptor content of benign breast epithelium may be related to breast cancer risk. The objective in this study was to compare the levels of estrogen receptor-α (ER) and progesterone receptor (PR) in nonneoplastic breast epithelium between breast cancer cases and biopsy controls. Methods: Between 1995 and 1997 at two sites (Women's College Hospital in Toronto and Kingston General Hospital), 667 women who were scheduled for diagnostic excisional breast biopsies completed a questionnaire providing personal information and agreed to allow analysis of routinely resected tissue. Histological slides with nonneoplastic epithelium were available for 101 cancer cases and 200 biopsy controls in Toronto and for 105 cancer cases and 119 controls in Kingston. Nonneoplastic epithelium was examined with immunohistochemical assays to determine the percent of epithelial cells staining for ER and PR. Unconditional logistic regression was used to calculate odds ratios (OR) stratified by study site. Results: The ER content of nonneoplastic tissue was higher in cases than biopsy controls in unadjusted analyses; after adjustment for age, however, a weak association remained in only one of the study sites. After adjustment for age, the PR content of nonneoplastic tissue was slightly lower in breast cancer cases than controls in one study site. Furthermore, this inverse association was confined to women with PR negative breast cancer in comparison to the controls. No interaction between ER and PR content of nonneoplastic tissue was observed in relation to the odds of having breast cancer. Conclusion: The results of this study are consistent with only a slight indication of increased ER levels in nonneoplastic tissue in breast cancer cases relative to controls. This study contributes to the understanding of breast cancer by examining both ER and PR in nonneoplastic tissue. Limitations remain, however, such as the necessity of using as controls women with benign breast changes, difficulties in selecting the appropriate tissue for analysis, and tissue sampling concurrent to diagnosis. Page 1 of 9 (page number not for citation purposes)