Six ESCC cell lines and 7 out of 25 PDX models derived from 188 biopsies with clear molecular features were employed to evaluate the sensitivity of several EGFR blockers in vitro and in vivo, as well as the underlying antitumor mechanisms of the most promising EGFR-TKI afatinib. This evidence concerns the gene EGFR and esophageal squamous cell carcinoma.