TKT and urinary bladder neoplasm: PsV-TK/GCV suicide gene therapy was evaluated in vivo after IVES instillation of 106 transducing relative units (TRU [21]) of PsV-TK in mice harboring day 4–5 MB49 bladder-tumors, followed 2 days later by a 10-days long daily ip GCV treatment as indicated in Figure 4A. Mice receiving PsV-TK-KO (a PsV expressing a non-functional TK protein [22]) and GCV or mice receiving PsV-TK without GCV were also used for comparing to untreated control mice.