ERBB2 and gastric cancer: The Trastuzumab for Gastric Cancer (ToGA) trial (ClinicalTrials.gov identifier, NCT01041404) demonstrated improvements in overall survival (OS) when trastuzumab was added to chemotherapy, compared with chemotherapy alone, in previously untreated patients with human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic gastric or gastroesophageal junction cancer [1].