Finasteride Treatment Alters Tissue Specific Androgen Receptor Expression in Prostate Tissues

BACKGROUNDNormal and pathologic growth of the prostate is dependent on the synthesis of dihydrotestosterone (DHT) from testosterone by 5-reductase. Finasteride is a selective inhibitor of 5-reductase 2, one isozyme of 5-reductase found in abundance in the human prostate. The objective of this study was to investigate the effects of finasteride on androgen receptor expression and tissue morphology in human benign prostatic hyperplasia specimens. METHODSPatients undergoing transurethral resection of the prostate and either treated or not treated with finasteride between 2004 and 2010 at the University of Wisconsin-Hospital were retrospectively identified using an institutional database. Prostate specimens from each patient were triple-stained for androgen receptor, prostate-specific antigen, and basal marker cytokeratin 5. Morphometric analysis was performed using the multispectral imaging, and results were compared between groups of finasteride treated and non-treated patients. RESULTSEpithelial androgen receptor but not stromal androgen receptor expression was significantly lower in patients treated with finasteride than in non-treated patients. Androgen receptor-regulated prostate-specific antigen was not significantly decreased in finasteride-treated patients. Significant luminal epithelial atrophy and basal cell hyperplasia were prevalent in finasteride treated patients. Epithelial androgen receptor expression was highly correlated to the level of luminal epithelial atrophy. CONCLUSIONSIn this study, finasteride decreased the expression of epithelial androgen receptor in a tissue specific manner. The correlation between epithelial androgen receptor and the extent of luminal epithelial atrophy suggests that epithelial androgen receptor may be directly regulating the atrophic effects observed with finasteride treatment. Prostate 74:923-932, 2014. (c) 2014 Wiley Periodicals, Inc.