INTRACELLULAR-LOCALIZATION OF TENASCIN IN SQUAMOUS-CELL CARCINOMA OF ORAL CAVITY - AN IMMUNOHISTOCHEMICAL STUDY

Tenascin is a multifunctional extracellular matrix glycoprotein genera lly expressed in epithelial tumors at sites of epithelial tumor-mesenc hymal tissue interface. Studies so far have indicated that mesenchymal cells are a major source of tenascin in tumor tissues. The present st udy evaluated biopsies and surgically resected specimens of oral squam ous cell carcinoma from 20 patients for the expression of tenascin usi ng immunohistochemical methods. The normal mucosa included in all surg ically resected specimens showed a delicate band in the submucosal con nective tissue, with infrequent breaks in continuity in the immediate vicinity of the basement membrane. The hyperplastic/hyperkeratinized o r dysplastic mucosa either showed a continuous band or enhanced expres sion of TN in the submucosal connective tissue. Evaluation of serial s ections for immunoreactivity of tenascin; particularly at the invading fronts of carcinomas of the buccal mucosa and tongue. The results of the present study may imply that despite the possible induction of ten ascinllfrom mesenchymal cells by carcinoma cells, carcinoma cells, if they produce tenascin, do so at the invasive fronts.