Immunohistochemical analysis of tenascin expression in different grades of oral submucous fibrosis

AIM: Tenascin, a glycoprotein, is one of the major constituents of extracellular matrix, which may function in organizing the stroma in normal and pathological conditions. The study aimed to correlate the structural organization of tenascin with the pathological progression of disease from early, moderate and advanced changes in oral submucous fibrosis (OSMF). STUDY DESIGN: A retrospective cross-sectional immunohistochemical (IHC) analysis of OSMF cases was performed. Total 70 slide samples were prepared for the study from 35 formalin-fixed paraffin-embedded tissue blocks with 10 each from histologically proven and graded as early, moderate and advanced OSMF and 5 of normal oral mucosa. The IHC sections were analyzed for the intensity and pattern of tenascin expression at the junction of epithelium and connective tissue (ECJ) and deeper connective tissue (CT), as well as presence or absence of staining around inflammatory cells, fibroblast and endothelial cells using anti-human tenascin. RESULT: Most of the OSMF cases showed retention of antigen at ECJ and in deeper CT. Its expression varied in different grades as well as around inflammatory cells, fibroblast and endothelial cells in same tissue section. Highly significant P values of 0.001 and 0.003 were obtained for tenascin intensity and pattern, respectively, at ECJ in different OSMF grades. In addition, for the expression of tenascin pattern in deeper CT among different OSMF grades, a significant P value of 0.018 was obtained. CONCLUSION: A differential expression of tenascin was observed with the progression of disease. The expression of tenascin as bright and continuous deposition at ECJ in early and moderate stages of OSMF signifies either proliferative organization within the overlying epithelium or an epithelial-mesenchymal interaction. However, a weak immunoreactivity of tenascin at ECJ was observed in advanced stage of OSMF.