Benign hyperplasia of the prostate (BPH) is the most common neoplasm of men in the United States. More than two thirds of males over age 50 have histologic evidence of BPH and by age 70 nearly one half have clinically palpable disease. As the disease progresses, urinary tract obstruction often necessitates clinical intervention. At present, the standard therapy for BPH is surgical resection. This form of therapy has considerable associated morbidity and mortality. Recently several therapeutic agents including androgen receptor blockers, alphal-antagonists, 5alpha-reductase inhibitors and gonadotropin releasing hormone super agonists have become available and could potentially form the basis for the medical management of BPH. It is the overall goal of this RFA (DK-92-18) to establish a national cooperative clinical trial group that would study the feasibility of such therapy. This application addresses the establishment of a Diagnostic Center to provide prognostic and follow-*up analysis of diagnostic specimens derived from the patients of the proposed pilot study. The methods to be employed include histopathology (light microscopy, special stains and image analysis), clinical chemistry (serum hormone and prostate-specific antigen levels) and ultrasound interpretation from both still and continuous images. In addition, molecular analysis of BCL2 in BPH biopsies is also proposed. The establishment of a centralized Diagnostic Center will provide standardized analysis and interpretation of diagnostic tests to assure that consistent results are obtained. In so doing, clinically meaningful strategies for the non-surgical treatment of BPH will be pursued.