Forced expression of FGF9 in prostatic epithelial cells disrupts prostate tissue homeostasis. A. In situ hybridization demonstrates expression of Fgf9 mRNA in the mouse prostate. Inserts are negative control using sense probes. B. H&E staining demonstrating prostate lesions in F9TG prostates at the indicated ages. Arrows indicate hyperplasia, LGPIN, and HGPIN. Inserts are high magnification views from the same slides. C. Quantitation of the histology of 18-month-old WT and F9TG prostates. N=4 per group. D. Immunostaining of Ki67 showing proliferating epithelial cells in 11-month-old WT and F9TG prostates. E. Quantitation of Ki67 positive cells in F9TG and control prostates at the indicated ages. F. Ki67 staining showing proliferating cells in the stromal compartment. G. Immunohistochemical or immunofluorescence analysis for androgen receptor, E-cadherin, α-smooth muscle actin, or CD3 expression in 18-month-old WT and F9TG prostates. WT, wild type; F9TG, FGF9 transgenic mice; HGPIN, high grade prostatic intraepithelial neoplasia; LGPIN, low grade prostatic intraepithelial neoplasia; F9TRAMP, FGF9TG/TRAMP bigenic mice; scale bars, 50 µm.