IMMUNOHISTOCHEMICAL AND ELECTRON-MICROSCOPIC STUDIES ON EPITHELIAL TUMOR-CELLS OF CYSTADENOLYMPHOMAS

Eosinophilic epithelial tumor cells of cystadenolymphomas consisted of two different cell types as determined by electron microscopy: light tumor cells, located on the apical side and containing mitochondria without cristae, and dark tumor cell, located on the basal side and containing mitochondria with large and tightly packed cristae and also lysosomes. As found immunohistochemically, keratins and other proteins were expressed differently in light (apical) and dark (basal) tumor cells. The dark tumor cells were positively stained by monoclonal antibody PKK1 (nos. 19, 18, 8; Carnoy's-fixed sections), K8.12 (nos. 16, 13; formalin-fixed sections), K4.62 (no. 19) and by monoclonals 115 F5 and 115 D8 against epithelial membrane antigens and by monoclonal KM231 against a human gastric cancer antigen. The immunohistochemical localization and pattern of staining is compared between dark tumor cells of cystadenolymphomas and ductal basal cells of the normal salivary gland.