Immunopathological study of neuropeptide expression in human salivary gland neoplasms

The immunoreactivity of anti-neuron-specific enolase (NSE) and anti-Leu-7 on formalin-fixed sections of human salivary gland neoplasms was determined by the avidin-biotin-peroxidase complex method. In addition, neuropeptides, such as vasoactive intestinal polypeptide, somatostatin, and substance P, in human salivary gland neoplasms were expressed, whereas other polypeptides, including glucagon, cholecystokinin, leu-enkephalin and calcitonin, were absent. When 182 paraffin-embedded examples of human salivary gland tumors, including 112 benign and 70 malignant neoplasms, were examined immunohistochemically, positive immunoreactivity was observed in: 51 cases with NSE (59%) and 46 cases with Leu-7 (54%) of 86 pleomorphic adenomas; 11 cases with Leu-7 (61%) of 18 Warthin's tumors; 7 cases with Leu-7 (58%) of 12 acinic cell carcinomas; 5 cases with NSE (31%) of 16 adenoid cystic carcinomas; 5 cases with NSE (42%) and 4 cases with Leu-7 (33%) of 12 adenocarcinomas; 4 cases with NSE (25%) and 6 cases with Leu-7 (38%) of 16 undifferentiated carcinomas. The other tumors, such as oxyphilic adenomas, basal cell adenomas, epidermoid carcinomas, and mucoepidermoid carcinomas, were nonreactive. Neuropeptides were observed in the neoplastic epithelial cells of certain tumors such as Warthin's tumors, acinic cell carcinomas, adenocarcinomas and undifferentiated carcinomas. These findings suggest the possibility that cells of neuroendocrine origin, present in certain neoplastic salivary gland epithelia may play a significant role in the histogenesis of human salivary gland neoplasms.