The reported frequency of HER2 overexpression in gastric carcinomas varies between 4.4 and 53.4% (weighted mean: 17.9%) (Jørgensen and Hersom 2012), and in carcinomas of the gastroesophageal junction and esophageal adenocarcinomas between 5 and 30%. Here, ERBB2 is linked to esophageal adenocarcinoma.