The highly tumorigenic and metastatic 253J B-V(R) human bladder transitional cell carcinoma (TCC) cell line (resistant to the antiproliferative effects of IFN-beta) was infected in vitro with adenoviral beta-galactosidase (Ad-LacZ), murine adenoviral IFN-beta (Ad-mIFN-beta), or human adenoviral IFN-beta (Ad-hIFN-beta) and implanted into the bladders of athymic nude mice.