Fig. 2

Photomicrographs illustrating Cytokeratin (AE1/AE3), Vimentin, p63, and CD31 immunostaining in IMPC of the canine mammary gland. Epithelial neoplastic cells exhibiting positive staining for Cytokeratin (AE1/AE3) staining in in situ (black arrow) and invasive regions (red arrows) of IMPC (a-b) (scale bar = 40 μm). Vimentin-positive labeling confirms the presence of a mesenchymal component in IMPC (c) (scale bar = 50 μm). Negative p63 staining in IMPC (d) (scale bar = 30 μm). Positive staining for CD31 is detected only in the plasma membrane of endothelial cells (see asterisks) (e-f) (scale bar = 50 μm). In situ regions are shown with black arrows and invasive regions with red arrows. (Novolink™ Polymer Detection System, counterstained with Harris’s hematoxylin)