Immunohistochemical expression of myofibroblasts, TGF-β1 and IFN-γ in oral fibrous lesions

Objective Analyze the presence of myofibroblasts (MFBs) in oral fibrous lesions and investigate TGF-β1 and IFN-γ expression by immunohistochemistry during their differentiation. Design Twenty giant cell fibromas (GCFs), 20 fibromas (FIBs), and 20 fibrous hyperplasias (FHs) were selected. To evaluate the presence of MFBs, anti-α-SMA-immunoreactive cells were quantified in connective tissue. TGF-β1 and IFN-γ expressions were evaluated in epithelial and connective tissue by determining the percentage of immunoreactive cells. Results Higher MFBs concentrations were observed in GCFs (median of 20.00), followed by FHs (15.00) and FIBs (14.00) (P = 0.072). No significant correlation between TGF-β1 or IFN-γ immunoexpression and the number of MFBs in oral fibrous lesions was observed (P > 0.05). Conclusions The higher density of MFBs found in GCFs, followed by FHs and FIBs, reaffirms the fibrogenic role of these cells, while the higher concentrations detected in GCFs, including evidence of giant MFBs, also suggest a role in the neoplastic behavior of these lesions. No correlation was observed between TGF-β1 and IFN-γ in the myofibroblastic transdifferentiation process of the analyzed lesions.