Abstract: Objective To study the effect of gene engineering adenovirus H101 treating esophagus carcinoma EC9706 induced by CEA gene specific silencing and to explore internal influential factor of H101 sensitivity. Methods To construct the siRNA expression vector of CEA and inhibit the expression of CEA through RNA interference and gene transfection in EC9706 cell, stable CEA gene silencing system were set up, compared with empty vector group and not transfected EC9706 cell, the model of athymic mouse subcutaneous transplantation tumor of human esophagus carcinoma EC9706 cell was established, injection in tumor was done with H101. The mRNA and protein expressions of CEA were detected by real time PCR and immunohistochemistry, the tumors'size were measured. Results Silencing CEA gene by applying RNAi can inhibit CEA mRNA and protein expression in nude mice model with transplanted human esophageal cancer cells, there was no evident influence on speed and volume of forming tumor. After using H101, the tumor size of interfering group was much less than empty vector group and normal control group, (P＜0.05）.Conclusion Inhibiting CEA expression in esophagus carcinoma EC9706 cell, the sensitivity of H101 can enhance .

Key words: CEA, gene engineering adenovirus, EC9706, nude mice