Immunohistochemical localization of fibroblast growth factors (FGFs) and FGF receptor-1 in human normal salivary glands and pleomorphic adenomas

Abstract

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 bFGFE, aFGF, and FGF receptor-1 in pleomorphic adenomas. In the normal salivary glands, bFGF was localized in the basement membranes of intercalated ducts, acini and basal cells of the excretory ducts, while aFGF was localized focally in the intercalated ductal cells and basal cells of the excretory ducts. In pleomorphic adenomas, bFGF was immunolocalized in the basement membranes around the solid nests of myoepithelial cells, around the neoplastic myoepithelial cells in the myxoid areas, and in the lacuna cells in the chondroid areas. In contrast, chondroid areas exhibited no immunoreactivity with aFGE. Positive signals for aFGF were localized in luminal cells of the tubuloglandular structures in pleomorphic adenomas. FGF receptor-1 immunolocalized in the lacuna cells and myoepithelial cells in the solid and myxoid areas. These observations suggest that bFGF and FGF receptor-1 produced by myoepithelial cells inhibited terminal differentiation and enchondral ossification in pleomorphic adenomas. These results also suggest important roles for FGFs in the formation of various structures with mesenchymal-like histology.