The CREB1‐deficient KYSE150 and KYSE30 cells were further overexpressed with wild‐type CREB1 and mutant CREB1 (K304E/K305E), respectively, and the results from chamber invasion assay showed that the repressed sensitivity to imperatorin in CREB1‐knockout ESCC cells was markedly restored when the cells were re‐overexpressed with wild‐type CREB1, but not the mutant, to a level comparable to parental cells (Figure 6E). Here, CREB1 is linked to esophageal squamous cell carcinoma.