E-cadherin and α-SMA expression in the epithelial-mesenchymal transition of salivary glands pleomorphic adenomas.

The pleomorphic adenoma, known also as mixed tumor of epithelioma with reshuffling stroma, is the most frequent salivary gland tumor, representing 45-75% of the total salivary gland tumors. In our study, we have investigated the immunohistochemical expression of E-cadherin and alpha-smooth muscle actin (α-SMA) in 15 cases of pleomorphic adenoma of salivary glands. We noticed the constant presence of E-cadherin reactivity at the level of luminal cells that cover the proliferative structures of ductal-cystic type, which gradually disappears to the periphery. At the level of epithelial proliferative solid areas, the reactivity for E-cadherin was inconstant and heterogeneous, while α-SMA expression increased. This aspect indicated the involving of epithelial-mesenchymal transition process in the evolution of pleomorphic adenoma.