Human epidermal growth factor receptor-2 gene amplification in gastric cancer using tissue microarray technology

Figure 1 Examples of human epidermal growth factor receptor-2 immunohistochemical expression and amplification in primary and metastatic gastric cancer. Immunohistochemistry shows strong membranous staining of human epidermal growth factor receptor-2 (HER2) in intestinal type gastric cancer (A) and (B) (× 400). Chromogenic in situ hybridization assay shows amplification of HER2 in primary gastric cancer (C) and the corresponding lymph node metastasis (D). Clustered green signals represent the amplified HER2 gene, while red signals represent centromere 17. Cell nuclei are counterstained with hematoxylin (× 1000).