IMMUNOREACTIVE HISTATIN-5 IN SALIVARY-GLAND TUMORS

Histatin is a group of histidine-rich polypeptides specific to parotid and submandibular gland secretions with several different biological functions such as stabilization of mineral-solute interaction in oral fluid, and antibacterial and antifungal actions. The authors generated polyclonal antibody to histatin by using purified histatin 5 as an im munogen and assayed the immunoreactivity by enzyme linked immunosorben t assay (ELISA) and immunoblotting. The antibody was further used to l ocalize histatin in normal and tumors of salivary glans, pleomorphic a denoma, Warthin's tumor, adenoid cystic, acinic cell, mucoepidermoid, papillary cystadenocarcinoma and undifferentiated carcinoma by immunoh istochemical methods. The normal major and minor human salivary glands showed an intense immunoreactivity in ductal cells, trace immunoreact ivity in serous acini and no immunoreactivity in mucous acinar cells, suggesting histatin in mainly produced by ductal cells and to a lesser extent by serous cells. A consistent immunoreactivity of histatin in ductal segments of normal glands and a variable expression in the tumo r cells of all the neoplastic lesions examined may implicate a role of this polypeptide in normal salivary gland function and salivary tumor s. In addition, the findings may implicate common precursor cells, how ever, differing in the state of differentiation in normal and neoplast ic conditions.