Figure 1.

a: MCM3 immunoreactivity in normal mucosa; MCM₃ expression is restricted to nuclei of basal cell layer and a few cells in the immediate suprabasal layers.  b: MCM3 immunoreactivity in mild epithelial dysplasia; MCM₃ expression is restricted to the lower third of the epithelium.  c: MCM3 immunoreactivity in severe epithelial dysplasia; MCM₃ positively stained nuclei are present throughout the epithelium.  d: MCM3 immunoreactivity in well-differentiated SCC; there are unstained foci of differentiating cells adjacent to keratin pearls.  e: MCM3 immunoreactivity in poorly differentiated SCC; MCM₃ expression is scattered throughout the malignant epithelial cells