Viruses have been shown to cause malignancy in a number of different animal systems. In recent years, members of the herpesvirus group and the oncornavirus group have been implicated in human malignancy. The purpose of this proposal is to investigate the role of the oncornaviruses in the malignant process of a single organ -- the prostate. Prostatic tissue will be obtained from patients with benign prostatic hyperplasia or prostatic carcinoma, as well as from normal individuals. The tissue will be examined histologically to determine the disease state of the prostate, and will be either grown in cell culture or assayed directly for the presence of oncornaviruses or their gene products. The techniques that will be used in this study include, electron microscopy and radioactive labeling methods for the detection of complete virus particles, and gel diffusion and radioimmunoassay for the detection of oncornaviral antigens. Tissues that are successfully grown as cell cultures will also be examined for the presence of oncornaviral components. In addition, attempts will be made to induce the production of oncornaviruses by the cell cultures in the event that they prove to be non-productive, using various methods in an effort to isolate a candidate human oncogenic virus. The combined approach outlined in this proposal will reveal the role that oncornaviruses play in carcinoma of the human prostate.