Objective:Study on the expression of Fas and Fas ligand (FasL) in gastric cancer and its possible significance.Methods:Fifty-eight paraffin-embedded gastric cancer tissues and twenty-six non-cancer tissues were tested for the expression of Fas and FasL protein by immunohistochemistry.Results:The positive rate of Fas in cancer cells of gastric cancer tissues was significantly lower than that in gastric epithelial cells of the control tissues(19.0% and 61.5%,respectively;?~2=14.918;P=0.000).The positive rate of FasL showed no significant difference between cancer cells of gastric cancer tissues and gastric epithelial cells of the control tissues(63.8% and 53.8%,respectively).Conclusion:The Fas-FasL system is unbalanced.It may be related to the carcinogenesis of gastric epithelial cells and might be responsible for the immune excape of these cells.

Objective: To study the expression of Fas, Fas ligand (FasL) and IFN ? in gastric cancer and its possible significance. Methods: Fifty eight gastric paraffin wax embedded cancer tissues and fifty three normal tissues adjacent gastric cancer were tested for the expression of Fas and FasL protein by immunohistochemistry and IFN ? mRNA by in situ hubridisation respectively. Results: The positive rate of Fas in cancer cells of gastric cancer tissues was significantly lower than that in gastric epithelial cells of the tissues adjacent cancer(19.0% and 64.2%, respectively; ? 2=23.46, P = 0.00). The positive rate of FasL in cancer cells of gastric cancer tissues was significantly higher than that in gastric epithelial cells of the tissues adjacent cancer(63.8% and 45.3%,respectively; ? 2=3.83, P =0.05). The positive rate of IFN ? in cancer cells of gastric cancer tissues was significantly lower than that in gastric epithelial cells of the tissues adjacent cancer(0.0% and 49.1%,respectively; ? 2=37.16, P =0.00). Conclusion: The Fas-FasL system was unbalanced, and the expression of IFN ? was low in gastric cancer cells in this study. These may be related to the carcinogenesis of gastric epithelial cells and might be responsible for the immune escape of these cells.

Objective To investigate cell-killing and bystander effects on gallbladder cancer (GBC-SD) cells transferred with double suicide genes (CD and HSV-tk). Methods CD and HSV-tk genes were transfected into PA317 cells using lipofectamine. GBC-SD cells were infected with viral supernatant. GBC-SD/CD+tk cells were treated with 5-FC and/or GCV. GBC-SD/CD+tk and GBC-SD were inoculated subcutaneously into the nude mice respectively and treated with GCV and 5-FC for 21 days. Results The killing effect of 5-FC and GCV in combination on GBC-SD/CD+tk cells is more effective than using 5-FC or GCV alone. The local bystander effect is significant while the distant bystander effect was not obvious. Conclusion The cell-killing efficacy of chemotherapy on GBC-SD transfected with double suicide gene was significantly increased, and the bystander effect was obvious.