Tumor-specific and tumor-associated cross-reactive antigens will be sought in carcinogen (FANFT)-induced Fischer rat bladder (transplantable and culturable) tumors; cross-reactive antigens will be characterized for possible association with embryonal and tissue components. The sites of these antigens on the tumor cells will be localized. During the process of tumorigenesis, the initial appearance of such antigens and their specific and cross-reactive potential will be sought sequentially. The possibility of immunosuppression of host responsiveness by either tumor growth or by carcinogen-feeding will also be studied.