AIM:To investigate the in vitro effects of suicide genetherapy system of herpes simplex virus thymidine kinasegene (HSV-TK) in combination with the treatment ofnucleotide analog-ganciclovir (GCV) on human pancreaticcancer,and to provide a novel clinical therapeutic methodfor human pancreatic cancer.METHODS:We used a replication defective recombinantretrovirus vector GINaTK (bearing HSV-TK gene) to makepackaging cell PA317 produce progeny virions.We thentransferred the HSV-TK gene to target cells SW1990 usingthese progeny virions,and treated these gene-modifiedtumor cells with GCV to study the sensitivity of the cells toGCV and their bystander effects by routine MTT-method.RESULTS:Packaging cell PA317/TK was successfullyconstructed,and we acquired SW1990/TK through virusprogeny infection.These gene-modified pancreatic cancercells were sensitive to the treatment of GCV compared withunmodified tumor cells (t=4.15,n=10,P<0.0025).We alsoobserved a remarkable bystander effect by mixing two kindsof cells at different ratio.CONCLUSION:Our data demonstrate that HSV-TK/GCVsuicide gene therapy system is effective for treatingexperimental human pancreatic cancer,which is largelyresistant to the common therapies,so the suicide genetherapy system may be a potential treatment approach forpancreatic cancer. To investigate the in vitro effects of suicide genetherapy system of herpes simplex virus thymidine kinasegene (HSV-TK) in combination with the treatment of nucleotide analog-ganciclovir (GCV) on human pancreatic cancer, and to provide a novel clinical therapeutic method for human pancreatic cancer .METHODS: We used a replication defective recombinant virus vector GINaTK (bearing HSV-TK gene) to make packaging cells PA317 produce progeny virions. We thentransferred the HSV-TK gene to target cells SW1990 using the progeny virions, and treated these gene-modified tumor cells with GCV to study the sensitivity of the cells to GCV and their bystander effects by routine MTT-method .RESULTS: Packaging cell PA317 / TK was successfully constructed, and we acquired SW1990 / TK through virus genrogen infection. The gene-modified pancreatic cancer cells were sensitive to the treatment of GCV compared withunmodified tumor cells (t = 4.15, n = 10, P <0.0025) .We alsoobserved a remarkable bystander effect by mixing two k indsof cells at different ratio. CONCLUSION: Our data demonstrates that HSV-TK / GCVsuicide gene therapy system is effective for treatingexperimental human pancreatic cancer, which is largelyresistant to the common therapies, so the suicide genetherapy system may be a potential treatment approach forpancreatic cancer.