Examples of quantitative human epidermal growth factor receptor 2 (HER2/neu) immunohistochemistry (IHC) scoring in gastroesophageal specimens based on consensus guidelines. A, Gastric adenocarcinoma specimen with HER2/neu IHC score of 0. B, Gastric adenocarcinoma specimen demonstrating HER2/neu IHC 1+ score. C, Example of gastric adenocarcinoma displaying HER2/neu IHC 2+ score. D, Gastroesophageal junction adenocarcinoma specimen demonstrating HER2/neu overexpression (IHC 3+) (HER2/neu IHC stain [HercepTest, Dako, Carpinteria, California], original magnifications ×400 [A through D]).