Much research has been conducted to determine which tissue (epithelium or stroma) in the prostate gives rise to benign prostatic hyperplasia (BPH). Considering that BPH displays two structural compartments, stromal and epithelial and that the periurethral and transitional regions are particularly involved, the immunohistochemical and regional evaluation of steroid receptors concentration, 5 alpha reductase, DHT and estrogen activity, may show important data on the role of these factors in BPH development. We started a immunohistochemical study on the epidermal growth factor (EGF) concentrations in the periurethral, central and pericapsular zones of BPH samples, considering the stroma-epithelium ratio; investigations are performed on BPH patients submitted to transvesical prostatectomy. Considering that the periurethral zone is particularly involved in BPH, the presence of high concentration of growth factors in this region, may support the concept of their involvement in BPH.