The apoptosis of tumor cells of ESCC xenografts in groups each was determined by an in situ TUNEL assay and the results showed that there were 63, 54, and 102 apoptotic cells/1,500 cells in mTOR siRNA, cisplatin, and mTOR siRNA + cisplatin groups, respectively, compared to control group (6 apoptotic cells/1,500 cells) (P < 0.05 or <0.01, Table 4). This evidence concerns the gene MTOR and esophageal squamous cell carcinoma.