1. Urology Service, Departments of Surgery and Clinical Investigation, Walter Reed Army Medical Center and Department of Genitourinary Pathology, Armed Forces Institute of Pathology, Washington, D. C., and Center for Prostate Disease Research, Department of Surgery, Uniformed Services University of Health Sciences, Laboratory of Comparative Carcinogenesis, National Cancer Institute and BCDP, PRI/Dyn Corporation, Frederick Cancer Research and Development Center, Frederick, Maryland.