Expression of Estrogen Alpha and Beta Receptors in Prostate Cancer and Hyperplasia: Immunohistochemical Analysis
Objectives: Estrogen receptors are believed to play a significant role in the pathogenesis of prostate carcinoma (PCa). The aim of this study is to evaluate the expression of ER-α and ER-β in human benign and malignant prostatic tissue.
Patients and Methods: The archival materials of 100 prostatic specimens (65 PCa, 35 BPH) were collected from the Department of Pathology, King Abdul-Aziz University Hospital, Jeddah, Saudi Arabia. Seven PCa cases contained foci of high-grade prostate intraepithelial neoplasia (HGPIN). Immunohistochemistry was used to test the protein expression of ER-α and ER-β utilizing monoclonal mouse antihuman antibodies.
Results: Among the 65 cases of PCa, ER-α was expressed in 3 cases (4.6%) in epithelial cells and 4 cases (6.1%) in stromal cells. ER-α was not expressed in any of the HGPIN foci. Additionally, ER-α was not expressed in either luminal or basal cells in any of the 35 BPH cases. However it was expressed in 4 cases (11.4%) in stromal cells of BPH. In PCa, ER-β was expressed in 61 cases (93.8%) and 35 cases (53.8%) in the epithelial and stromal cells respectively. ER-β was expressed only in 2 cases (28.5%) out of 7 HGPIN foci. It was expressed in 33 cases (94.3%) of epithelial
and stromal cells of BPH. Conclusion: The majority of PCa and BPH exhibited nuclear immunoreactivity for ER-β in both tumor and stromal cells and they are usually negative for ER-α. There is probably partial loss of ER-β in HGPIN. ER-β may have a role in the process of prostatic hyperplasia and malignancy.
Key Words: ER-α, ER-β, prostate, hyperplasia, premalignant, cancer, immunohistochemistry