中文摘要：

RNA干扰（RNAi）是一种由双链RNA介导的基因沉默现象。RNAi作为强有力的研究工具正在基因功能组学领域掀起一场真正的革命，也成为当今肿瘤基因治疗研究的热点。条件增殖腺病毒（CRAd）是一类仅在肿瘤细胞内特异增殖新型腺病毒载体，通过CRAd介导的小干扰RNA（siRNA）可以靶向肿瘤细胞，且随着病毒增殖反复表达siRNA，进一步加强siRNA介导的癌基因沉默效果。因此，siRNA-CRAd模式开辟了肿瘤基因治疗的新途径。

英文摘要：

RNA interference （RNAi） is a phenomenon of gene silence initiated by double-stranded RNA. As a powerful tool, RNAi arouses a great revolution in gene functional research area and becomes a focus in cancer gene therapy area. Conditionally replicative adenoviruses（CRAd） represent a novel class of adenoviruse carrier which selectively replicate in tumor cells,but not in other normal cells. CRAd can restrict small interfering RNA （siRNA） expression within the tumor microenvironment and renew repeatedly siRNA with viral replication which further reinforce outcome of siRNA-mediated oncogene silencing. The concept of carrier-restricted delivery of siRNA by CRAds provide a new method for cancer gene therapy.