ERBB2 and gastric cancer: The Trastuzumab for Gastric Cancer study (ToGA) revealed 22% of HER2-positive GEC, but HER2 positivity frequency differed according to the localization and histologic classification, with esophagogastric junction tumors (EGJ) and gastric tumors (GC) presenting 32.2 and 21.4% of positivity, respectively (9).