Immunoprofile of reactive salivary myoepithelial cells in intraductal areas of carcinoma ex-pleomorphic adenoma.

The myoepithelial cell (MC) is a component of various secretory glands, including salivary glands. Besides its function, a tumor suppressor and a tumor facilitating functions have been attributed to this cell. We investigated the immunoprofile of benign MC in intraductal areas of carcinoma ex-pleomorphic adenoma (CXPA), comparing them with the MC in duct-like areas of pleomorphic adenoma, origin of the malignant tumor. Antibodies against myoepithelial markers-CK14, alpha-SMA, calponin, P63, CD10, and D2-40-plus laminin and maspin was applied in four selected cases of intracapsular and minimal invasive CXPA with only luminal differentiation presenting areas of intraductal carcinoma. The immunohistochemical reactions of all the antibodies showed stronger staining in benign MC surrounding the malignant epithelial cells than in benign MC in duct-like areas of pleomorphic adenoma, thus revealing that in the malignization process the benign MC become differentiated and produce important proteins related to the tumor suppressor function.