Furthermore, the treatment strategy varies between ESCC and EAC; human epidermal growth factor receptor 2 (HER2)/ERBB2 status evaluation plays a role in EAC treatment decisions for adding trastuzumab in advanced disease, but there are no recommendations in the guidelines regarding the HER2 evaluation and the addition of trastuzumab for ESCC. This evidence concerns the gene ERBB2 and esophageal squamous cell carcinoma.