Oestrogen receptor-β1 but not oestrogen receptor-βcx is of prognostic value in apocrine carcinoma of the breast
Apocrine carcinoma of the breast, which frequently expresses oestrogen receptor-β (ER-β) in the absence of ER-α and only infrequently is treated endocrinologically, gives an opportunity to investigate the clinicopathological role of ER-β in breast cancer independent of ER-α expression or tamoxifen treatment. Several isotypes of ER-β, ER-β1–5 etc., have been identified thus far; however, the clinicopathological importance of each ER-β isotype in breast cancer is still uncertain. Here we aimed to clarify the clinicopathological importance of ER-β1 and ER-βcx (ER-β2) in apocrine carcinomas, immunohistochemically examining expressions of ER-β1 and ER-βcx in 47 apocrine carcinomas. Positivity for ER-β1 and ER-βcx was observed in 41 (87%) and 18 (38%) of 47 cases, respectively. ER-β1 positivity was related to smaller tumor size (P=0.0359), lower histological grade (P=0.0322), and higher disease-free survival (P<0.0001), whereas ER-βcx status was related to none of these parameters. ER-β1 positivity was also associated with favorable clinical outcome in 24 so-called triple-negative (ER-α-negative/PR-negative/HER2-negative) apocrine carcinomas. ER-β1 itself, independent of ER-α expression and tamoxifen treatment, seems to have a tumor-suppressive effect, at least in apocrine carcinomas. Further study of ER-β1 is desired to optimize breast cancer treatment.
Document Type: Original Article
Affiliations: 1: Division of Clinical Trials and Research, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo 2: Research Team for Geriatric Diseases, Tokyo Metropolitan Institute of Gerontology, Tokyo 3: Department of Breast Pathology, Cancer Institute, Tokyo 4: Department of Biochemistry, Fujita Health University School of Medicine, Toyoake, Aichi, Japan 5: Department of Pathology, Baylor College of Medicine, Houston, USA 6: Department of Breast Oncology, Cancer Institute Hospital, Tokyo 7: Department of Surgery (Breast Surgery), Graduate School of Medicine Kyoto University, Kyoto, Japan
Publication date: 2008-10-01