Of note, comparatively few studies related to EGFR and HER3 expression in upper gastrointestinal cancer have included the esophagus, which is somewhat surprising considering the increasing incidence of esophageal adenocarcinoma and indications of better EGFR TKI response in esophageal than gastric adenocarcinoma[13]. This evidence concerns the gene ERBB3 and gastric adenocarcinoma.