HER2 aberrations and heterogeneity in cancers of the digestive system: Implications for pathologists and gastroenterologists

Figure 3 Representative micrographs of a gastric adenocarcinoma showing heterogeneous erbB2 immunohistochemical expression. In this paradigmatic example of HER2 heterogeneity in gastric cancer, the tumor showed the coexistence of 2+ (A), 3+ (B, C), and negative areas (C), with the former immunohistochemical pattern involving the majority of the tumor cells. Original magnification × 200.