A comparative study on the immunolocalization of keratin and myosin in salivary gland tumors.

Surgical specimens of the salivary gland tumor were studied by immunohistochemical techniques using the anti-keratin antibody and the anti-myosin antibody. In the normal tissue, keratin was localized predominantly in the duct epithelial cells and myosin in the myoepithelial cells. According to the immunohistochemical staining patterns, the tumors were able to be divided into two groups: one group consisted of pleomorphic adenoma, adenoid cystic carcinoma, and adenocarcinoma which showed a mixture of keratin- and myosin-positive cells, respectively, mimicking the structures of the intercalated duct; the other comprised monomorphic adenoma and mucoepidermoid tumor which disclosed keratin-positive cells predominantly, resembling the constituent of the excretory duct. These results were mostly consistent with the "bicellular theory" that the salivary tumors generate from the intercalated duct reserve cells and the excretory duct reserve cells.