FGF7 and FGF2 are increased in benign prostatic hyperplasia and are associated with increased proliferation

Purpose: To determine if overexpression of FGF7 and FGF2 occurs in benign p rostatic hyperplasia (BPH) and if so, whether such overexpression is correl ated with increased proliferation of epithelial and/or stromal cells. Materials and Methods: The FGF7 and FGF2 content of protein extracts of nor mal peripheral zone, normal transition zone and hyperplastic prostatic tiss ues were determined by enzyme-linked immunoabsorption assay. Proliferation of epithelial and stromal cells was assessed by immunohistochemistry with a nti-Ki67 antibodies on frozen sections of the same tissues used for protein extraction. The in vitro effects of FGF7 and FGF2 on proliferation were as sessed by addition of recombinant growth factor to primary cultures of pros tatic epithelial and stromal cells. Results: We have found that both FGF7 and FGF2 are overexpressed in hyperpl astic prostate in comparison to normal peripheral and transition zone tissu e. FGF7 is a potent mitogen for epithelial cells in culture. Consistent wit h these in vitro effects, quantitative analysis of cellular proliferation b y Ki67 immunohistochemistry revealed a strong correlation of epithelial pro liferation with FGF7 content in BPH tissue, consistent with a key role for this growth factor in driving the abnormal epithelial proliferation in BPH, FGF2 is mitogenic for stromal cells in culture and there was a weaker corr elation of FGF2 content with increased stromal proliferation. Conclusion: Overexpression of FGF7 and FGF2 may play an important role in t he abnormal cellular proliferation seen in benign prostatic hyperplasia.