Figure 1

Merkel cell carcinoma: (a) Notch-1 cytoplasmic and membranous staining in Merkel cell carcinoma tumor cells (original magnification × 10); (b) Notch-1 is also strongly expressed in endothelial cells of capillary vessels in the context of the tumor (original magnification × 40); (c) strong membranous staining for β-catenin (original magnification × 40); (d) E-cadherin positivity is observed at the membrane level only in rare scattered cells (original magnification × 20); inset shows that the overlying epidermis is strongly E-cadherin positive with a membranous pattern (internal positive control) (original magnification × 10).