Objective:To evaluate the effectiveness of intratumoral and intraperitoneal injection with retrovirus HSVtk gene on mouse bladder cancer.Methods:Subcutaneous and intraperitoneal bladder tumor was respectively established with mouse cancer cell line(T739) in syngeneic mice.Direct intratumor injection of retroviral HSVtk into the subcutaneous tumor was performed.In peritoneum cavity tumor model

HSVtk gene was transferred by intraperitoneal injection of retrovirus vector carrying HSVtk gene.After GCV therapy the tumor volume and animal survival time were monitored.Results:Both animal models were successfully induced in all mice within one week following subcutaneous and intraperitoneal injection of T739 cells.Compared with control animals

the tumor growth in both models was significantly inhibited with HSVtk/GCV system

and also the animal survival time was prolonged with administration of GCV(P<0.05).Tissue hybridization in situ confirmed the expression of HSVtk gene in mouse bladder tumors.Conclusion:Bladder tumor inoculated in mice can be retrovirally transfected with HSVtk gene by intra-tumor or intra peritoneal injection.Combined with administration of GCV

HSVtk gene significantly inhibits the bladder tumor growth.