Immunohistochemical localisation of EphB4 expression in three different colon cancers and matched normal mucosa. The brown stain from the biotinylated secondary antibody indicates the EphB4 protein. Nuclei are stained with Harris haematoxylin and appear blue. High power (100X) magnification images of three different adenocarcinomas (well differentiated, moderately well differentiated and poorly differentiated) and their matched normal mucosa are shown. Strong staining of the tumour tissue and very weak, diffuse staining of normal tissue was evident for each sample set. There was no cross-reactivity with the secondary antibody alone (result not shown).