Cellular localization of fibroplast growth factor 2 (FGF-2) in benign prostatic hyperplasia

Fibroblast growth factor 2 (FGF-2, basic fibroblast growth factor) has been reported to be elevated in tissues from benign prostatic hyperplasia (BPH) , the most frequent neoplastic disease in aging men. This suggests that FGF -2 may play a significant role in the development of BPH. In this study the cellular distribution pattern of FGF-2 in tissues from BPH has been invest igated by immunohistochemical and molecular biological methods. Radioimmuno assay revealed high concentrations of FGF-2, ranging between 450 and 950 ng per g tissue. Immunoblots confirmed the presence of a 18 kDa FGF-2 in tiss ue extracts. By immunohistochemistry done with a polyclonal antibody to rec ombinant FGF-2 on paraffin sections, FGF-2 was localized in fibroblasts, en dothelial cells and smooth muscle cells of tissue samples of BPH. Nuclei of these cells were labelled distinctly. Moreover the cytoplasm of smooth mus cle cells was labelled moderately. No immunostaining was seen in prostatic epithelium. Nonradioactive in situ hybridization with digoxygenin-labelled oligonucleotides revealed the presence of mRNA for FGF-2 in smooth muscle c ells of the prostatic stroma. These results provide evidence that FGF-2 may be produced locally in the human prostate as a stroma-specific mitogen and may play a causal role in the development of BPH.