Overexpression of IGF-1r in tumors has been demonstrated in some reports [19, 20], so to test the hypothesis that IGF-1r silencing may increase the therapeutic efficacy of radiotherapy in the treatment of ESCC, a combination of IGF-1r siRNA and radiation therapy was tested in vitro and in vivo. This evidence concerns the gene IGF1R and esophageal squamous cell carcinoma.