ERBB2 and gastroesophageal junction adenocarcinoma: HER2-targeted agents came into prominence for GEA in 2010, with the phase III ToGA clinical trial demonstrating an improvement in overall survival with the addition of trastuzumab to systemic chemotherapy (Table 1) in patients with locally advanced, recurrent, or metastatic gastric or GEJ adenocarcinoma demonstrating HER2 overexpression [6].