LOCALIZATION OF GLYCOSAMINOGLYCANS (GAGS) IN PLEOMORPHIC ADENOMA (PA)OF SALIVARY-GLANDS - AN IMMUNOHISTOCHEMICAL AND HISTOCHEMICAL EVALUATION

The tumor matrix of salivary pleomorphic adenoma (PA) is characteristi cally rich in glycosaminoglycans (GAGs), which contribute to its compl ex histoarchitecture. This study evaluated the microscopic localizatio n of various GAGs in 17 PAs, using a panel of anti-GAG monoclonal anti bodies and biotinylated hyaluronic acid (HA)-binding protein. Both epi thelial and mesenchymal-like tissues were confirmed to contain GAGs. L uminal epithelial cells mostly lacked GAGs, whereas GAGs were seen bot h in the cytoplasm and cell membrane of non-luminal epithelial cells. In addition, small intercellular accumulations of GAGs were often pres ent in solid epithelial areas, implying the epithelial origin of GAGs. GAGs did not appear to be a main component of the hyaline matrix. The myxoid region was consistently stained for both chondroitin 6-sulfate (CS-6) and HA but variably for chondroitin 4-sulfate (CS-4), dermatan sulfate (DS) and keratan sulfate (KS); heparan sulfate (HS) was not d etected. The chondroid region showed increased staining for CS-6 but r educed staining for HA when compared with the myxoid region. In additi on, CS-4, DS and KS were seen both in chondroid cells and the territor ial matrix, whereas HS was present only in the cells. It is suggested that GAGs in PA are mainly produced by non-luminal cells and influence the proliferation, differentiation, secretory activity and shape of t umor cells, thus contributing to the morphological diversity of this t umor.