Abstract

An immunohistochemistry for S-100 protein by biotin avidin system technique was done to evaluate the existence and distribution pattern of S-100 protein positive cells in various obtained were as follows. 1) Positive immunostaining for S-100 protein was observed in myoepithelial cell, serous acinar cell and nervous bundle in normal salivary gland. 2) Strong immunoreactivity for S-100 protein was shown in plemorphic adenoma, which was localized not only in myoepithelial cord or sheets of epithelial portion but also in chondrocytes, stellate cells of myxoid stroma and in squamous keratin pearl of mesenchymal metaplastic foci. 3) The S-100 protein was demonstrated in the tumor cells of tubular adenoma, acinic cell tumors and in epidermoid area of mucoepidermoid tumors. 4) Immunoreactivity for S-100 protein, however, was not found in the tumor cells of adenoid cystic carcinoma and adenolymphoma except for stroma reticulum cells. 5) Intensity of positive reaction for S-100 protein varied from cell to cell: Some had intense immunoreactivity, whreas others were only weakly positive or completely negative, even in myoepithelial cell nest of the same pleomorphic adenoma.