ERBB2 and esophageal adenocarcinoma: Accordingly, most current preclinical and clinical studies are focused on esophageal adenocarcinoma and literature data supports a correlation between HER-2 gene expression (or amplification) and Trastuzumab efficacy in esophageal adenocarcinoma (preclinical and clinical phase I/II data [10,31] however, such data is rare in esophageal squamous cell carcinoma [32].