HER2 phrase remains a biomarker that is important guide the addition associated with monoclonal antibody trastuzumab to first-line systemic chemotherapy in unresectable, metastatic gastroesophageal adenocarcinomas (GEA). Progress and challenges in HER2-positive gastroesophageal adenocarcinoma Abstract nevertheless, in contrast to cancer of the breast, other HER2-targeted methods of date never have improved outcomes in this molecular subtype