Expression of estrogen receptor β and Ki 67 in benign & malignant human prostate lesions by immunohistochemistry.

Estrogen regulates the growth of prostate through two receptors Estrogen receptor α & β of which ERβ is proposed to be antiproliferative. There is a wide variation in the results of various studies regarding the localisation, level of expression of ERβ in benign & malignant lesions of prostate and its relation to the grade of tumor emphasizing the need for additional studies to standardize the distribution of this receptor in prostate. This was a prospective study conducted in Department of Pathology, UCMS, Delhi, evaluating ERβ & Ki 67 immunoexpression in 60 cases of benign and malignant lesions of prostate (30 each). Tissue for study included prostatic core biopsy and TURP chips. After histomorphological diagnosis, immunohistochemical staining was performed using a monoclonal antibody. Nuclear expression of ERβ & Ki67 was evaluated and compared between the two study groups (benign & malignant lesions) using Pearson chi square test. ERβ was predominantly localized to nuclei of secretory epithelium of prostatic glands. Expression of ERβ was higher in benign glands compared to carcinoma. However, majority of carcinomas retained ERβ expression though at much lower levels. Expression of Ki 67 was higher in carcinoma than benign hyperplasia. There was no correlation between the ERβ status, Ki 67 expression & grade of tumor. Expression of ERβ is downregulated in carcinoma compared to benign hyperplasia and is consistent with its chemopreventive role in prostate. It might have a therapeutic implication as agonists' targeting this receptor could be a part of treatment protocol for those patients of carcinoma who retain this receptor at significant levels.