Immunolocalization of cell signaling molecules in the granular cell ameloblastoma

Background: Bone morphogenic protein (BMP) and Wnt signaling pathway molecules play important roles in cytodifferentiation and cell proliferation. We attempted to localize these signaling molecules in the granular cell ameloblastoma. Materials and methods: Four samples of paraffin-embedded ameloblastoma with granular cells were studied. Immunohistochemistry was performed to detect basement membrane type heparan sulfate (HS) (JM403), cell surface type HS (10E4), heparanase, Wnt-5a, Wnt-2, β-catenin, and BMP-4. Results: In all four samples, strong expression of β-catenin and Wnt-5a was detected within the granular cells, while BMP-4 expression was weak and Wnt-2 was negative. Immunoreactivities of basement membrane type HS, cell surface type HS, and heparanase were variable within granular cells in ameloblastoma. Conclusion: Granular cells in ameloblastoma exhibit abnormal biological behaviors, particularly synthesis and secretion of protein. Synthesis of signaling molecules is upregulated, but secretion is arrested in some cases, while both are lost in other cases.