Expression of E-Cadherin, β-Catenin and APC protein in Canine Colorectal Tumours

A, Well-differentiated papillary adenocarcinoma showing APC protein to be strongly expressed by many cells. The immunolabelling is evident at the luminal pole of neoplastic cells. (Streptavidin-biotin peroxidase; Bar=20 μm); B, Well-differentiated papillary adenocarcinoma. Cytoplasmic β-catenin distribution with nuclear positivity is evident in some cells (arrows). Membranous distribution is also shown. (Streptavidin-biotin peroxidase; Bar=20 μm); C, Poorly differentiated tubular adenocarcinoma. Immunostaining for APC protein showing complete negativity (Streptavidin-biotin peroxidase; Bar=20 μm); D, Poorly differentiated tubular adenocarcinoma showing β-catenin distributed in the cytoplasm of many neoplastic cells. (Streptavidin-biotin peroxidase; Bar=20 μm); E, Dysplasia. β-Catenin immunostaining, corresponding to red TRITC immunofluorescence, with a membranous distribution in many cells. Cytoplasmic distribution is evident in few cells. (Two-colour immunofluorescence. Bar=40 μm); F, Dysplasia. APC immunostaining, corresponding to green FITC imunofluorescence, with strong expression in many cells. (Two-colour immunofluorescence. Bar=40 μm); G, Dysplasia. Coexpression of APC and β-catenin, evident in yellow, shows the colocalization of both protein in many cells. (Two-colour immunofluorescence. Bar=40 μm); H, Well-differentiated tubular adenocarcinoma. β-Catenin immunostaining, corresponding to red TRITC immunofluorescence, is membranous in many cells. Cytoplasmic distribution is evident in some neoplastic cells (arrows). (Two-colour immunofluorescence. Bar=40 μm); I, Well-differentiated tubular adenocarcinoma. APC protein immunostaining, corresponding to green FITC imunofluorescence, with weak expression in many cells and negativity in the cells with cytoplasmic β-catenin distribution (arrows). (Two-colour immunofluorescence. Bar=40 μm); J, Well-differentiated tubular adenocarcinoma. Coexpression of both β-catenin and APC protein confirms the cytoplasmic distribution of β-catenin in APC-negative cells (arrows). (Two-colour immunofluorescence. Bar=40 μm); K, Poorly differentiated tubular adenocarcinoma. β-Catenin immunostaining, corresponding to red TRITC immunofluorescence, with cytoplasmic distribution in many neoplastic cells (arrows). (Two-colour immunofluorescence. Bar=40 μm); L, Poorly differentiated tubular adenocarcinoma. APC protein immunostaining, corresponding to green FITC imunofluorescence, shows the absence of protein in many neoplastic cells (arrows). (Two-colour immunofluorescence. Bar=40 μm); M, Poorly differentiated tubular adenocarcinoma. Coexpression of both β-catenin and APC protein confirms the cytoplasmic distribution of β-catenin in APC-negative cells (arrows). (Two-colour immunofluorescence. Bar=40 μm);