Expression of basic fibroblast growth factor and its receptors FGFRI and FGFR2 in human benign prostatic hyperplasia treated with finasteride

BACKGROUND. The development of benign prostatic hyperplasia (BPH) is an and rogen-dependent process which may be mediated by a number of locally produc ed growth factors. One of these, the basic fibroblast growth factor (bFGF o r FGF2), has a mitogenic effect on prostatic stroma. High expression levels of bFGF have been reported in BPH. FGFR1 and FGFR2 receptors, that exhibit affinity for bFGF, have been identified in normal and hyperplastic prostat e. Finasteride, a 5 alpha-reductase inhibitor, is an effective drug in the treatment of BPH, inducing regressive changes in the prostate of treated pa tients, even though its mechanisms of action are not yet completely elucida ted. This study was designed to assess the effects of finasteride on the ex pression levels of bFGF, FGFR1, and FGFR2 in patients with BPH. METHODS. The expression levels of bFGF, FGFR1, and FGFR2 in 9 patients with prostatic hyperplasia treated with finasteride were assessed by immunohist ochemistry and reverse transcription-polymerase chain reaction (RT-PCR) ana lysis of mRNA expression and were compared with those of 9 control patients with untreated BPH. RESULTS. Immunohistochemistry showed strong bFGF immunoreactivity in the pr ostatic stroma of untreated patients, this being somewhat weaker in the epi thelium. In treated patients, epithelial immunoreactivity was practically n egative, and a considerable reduction in stromal immunoreactivity was seen. These findings were also confirmed by RT-PCR. FGFR1 showed a weak immunore activity in the stroma and in basal epithelial cells. FGFR1 showed a weak i mmunoreactivity in the stroma and in basal epithelial cells. FGFR2 exhibite d strong stromal immunoreactivity, becoming weaker in the basal epithelium. No differences were seen in the expression of both receptors between the g roups of treated and untreated patients. CONCLUSIONS. A marked reduction in bFGF levels is seen in BPH treated with finasteride in comparison to untreated BPH. Ln our opinion, finasteride may act as a negative regulator of bFGF expression, counteracting the role of bFGF in the development of BPH. Prostate 40:83-88, 1999. (C) 1999 Wiley-Lis s, Inc.