The research project entails the establishment and characterization of an animal model of human prostatic cancer and its use in studies of the immunologic aspects of this disease. Specifically, we wish to determine whether treatment of the primary prostatic tumor by cryosurgery would cause the regression of metastatic disease and what role; if any, the immune response(s) plays in this regression. Towards this end we have been utilizing a transplantable adenocarcinoma of the inbred Copenhagen strain of rat. Tumors have been produced by both subcutaneous and intraprostatic inoculation of defined numbers of cells. In animals bearings prostatic tumors we have been able to demonstrate metastatic lesions in the draining lymph nodes and lung. Experiments planned for the immediate future include: (1) development of an assay that will enable us to detect metastatic disease in rats other than by surgical exploration, (2) study the effect of cryosurgery on the growth of the primary and metastatic tumor, (3) demonstration of immune responses to tumor antigens after cryosurgery and (4) the correlation between the effect of cryosurgery on the tumor and these immune responses.