In colony‐forming experiment, the number of clones of nontransfected and transfected shRNA scramble, shRNA Ku80 ESCC cells was shown in Figure 4A. The difference between nontransfected ECA109 and KYSE150 cells and shRNA Ku80‐transfected cells have statistical significance (ANOVA; P < 0.001, P < 0.001). This evidence concerns the gene XRCC5 and esophageal squamous cell carcinoma.