SIMPLE MUCIN-TYPE TN AND SIALOSYL-TN CARBOHYDRATE ANTIGENS IN SALIVARY-GLAND CARCINOMAS

Background. Neoplastic transformation is associated frequently with ch anges in the glycosylation process. Simple mucin-type glycosylation in cancer cells has been found to be characterized by incomplete synthes is with precursor accumulation, leading to the exposure of the structu res Tn and sialosyl-Tn, which are normally cryptic in human cells and secretions, including saliva and salivary glands. Methods. Paraffin se ctions from 50 salivary gland carcinomas of different histologic types were investigated with immunohistologic studies and a panel of monocl onal antibodies with well-defined specificity for Tn and sialosyl-Tn. Results. Tn and sialosyl-Tn antigens were expressed in the cytoplasm o f glandular differentiated cells; in the luminal membranes and mucinou s content of the glandular differentiated areas in almost all mucoepid ermoid carcinomas and adenocarcinomas; and in carcinoma in pleomorphic adenoma, when the malignant component was an adenocarcinoma. In contr ast, acinic cell carcinomas and adenoid cystic carcinomas expressed on ly minimal amounts of Tn and sialosyl-Tn, and the staining was seen on ly in relation to the luminal membrane and mucin of a few glandular st ructures. Conclusions. Mucin-type Tn and sialosyl-Tn may be regarded a s markers of a glandular differentiation pattern in salivary gland car cinomas. The cellular location of the antigen-antibody complex indicat es that they are synthesized and secreted from the tumor cells into sa liva or serum.