Monoclonal antibody to keratin K8.12 expression in ductal basal cells of obstructive lesions and in outer tumor cells of salivary pleomorphic adenomas
Acta Histochemica et Cytochemica
Monoclonal antibody for keratin K8.12 (keratin nos. 13 and 16) was evaluated in paraffin sections of 17 cases of obstructive sialadenitis and 97 pleomorphic adenomas. In normal salivary glands fixed with 10% formalin, K8.12 staining was strongly limited to ductal basal cells, and staining to PKK1 and KL1 was positive in duct cells. Monoclonal antibodies PKK1 and KL1 were compared in duct-like structures of obstructive lesions and pleomorphic adenomas. Duct-like structures in obstructive lesions
... obstructive lesions showed strong staining for K8.12 in ductal basal cells, and positive staining for PKK1 and KL1 in ductal epithelial cells, in different stages of ductal obstruction. Pleomorphic adenomas showed an intense expression for K8.12 staining in outer tumor cells of tubulo-ductal structures, and positive reaction for PKK1 and KL1 in luminal tumor cells. The histogenesis of pleomorphic adenoma is discussed in terms of the immunohistochemical labelling of the 3 types of monoclonal antibodies to keratin. The identification of a progenitor cell to ductal basal cells is also hypothesized. Salivary glands are composed of terminal acinar components and ductal segments, and ductal epithelium also consists of ductal basal cells and luminal cells. Recently, the histogeneses of salivary gland tumors have been evaluated to immunohistochemically detect ductal basal cells as specific staining to keratin proteins (3, 8, 12, 14, 18, 27, 33, 34) and many monoclonal antibodies to keratins were decorated to ductal epithelial cells (5-7, 21-23, 31, 32). Preceding papers have reported that pleomorphic adenomas co-expressed keratin and vimentin (6, 23, 31) , and that PKK1 and KL1 decorated luminal tumor cells of tubulo-ductal structures of such benign tumors (21, 22) . The present study describes the distribution of keratin stained by monoclonal antibody K8.12 (nos 13, 16) in obstructive sialadenitis and pleomorphic adenomas, which showed different staining patterns compared with those observed by staining with monoclonal antibodies PKK1 and KL1.