IMMUNOHISTOCHEMICAL LOCALIZATION OF FIBROBLAST GROWTH-FACTORS (FGFS) AND FGF RECEPTOR-1 IN HUMAN NORMAL SALIVARY-GLANDS AND PLEOMORPHIC ADENOMAS

Basic and acidic fibroblast growth factors (bFGF and aFGF) are heparin -binding growth factors, and promote fibrogenesis and angiogenesis. We investigated the immunohistochemical localization of bFGF, aFGF, and FGF receptor-1 in pleomorphic adenomas. In the normal salivary glands, bFGF was localized in the basement membranes of intercalated ducts, a cini and basal cells of the excretory ducts, while aFGF was localized focally in the intercalated ductal cells and basal cells of the excret ory ducts. In pleomorphic adenomas, bFGF was immunolocalized in the ba sement membranes around the solid nests of myoepithelial cells, around the neoplastic myoepithelial cells in the myxoid areas, and in the la cuna cells in the chondroid areas. In contrast, chondroid areas exhibi ted no immunoreactivity with aFGF. Positive signals for aFGF were loca lized in luminal cells of the tubuloglandular structures in pleomorphi c adenomas. FGF receptor-1 immunolocalized in the lacuna cells and myo epithelial cells in the solid and myxoid areas. These observations sug gest that bFGF and FGF receptor-1 produced by myoepithelial cells inhi bited terminal differentiation and enchondral ossification in pleomorp hic adenomas. These results also suggest important roles for FGFs in t he formation of various structures with mesenchymal-like histology.