Transforming Growth Factor-α and Oral Fibroma: Immunohistochemical and in Situ Hybridization Study

Purpose: Transforming growth factor-α (TGF-α) is usually expressed in cell lines derived from sarcomas. It is known as a mitogen for fibroblasts. The aim of this study was to determine whether there were any differences in the expression pattern of TGF-α between normal oral mucosa and oral fibroma. Patients and Methods: Fourteen pathologic specimens (6 males and 8 females; 37.2 ± 23.2 years) and 10 normal oral mucosal specimens (5 females and 5 males; 43.8 ± 17.7 years) were used for this study. Identification of TGF-α was sought by using immunohistochemistry and in situ hybridization. Results: The samples from normal oral mucosa did not express TGF-α. One sample from oral fibroma did not express TGF-α (7.1%). Five samples from oral fibroma expressed TGF-α sparsely (35.7%). Eight samples showed diffuse expression of TGF-α (57.1%). The immunopositive reaction to TGF-α in oral fibroma was localized in the basal layer and the fibroblasts that resided beneath the epithelium. This pattern was also shown in the in situ hybridization study as well. Conclusion: TGF-α is expressed in oral fibromas. It suggested that TGF-α might play a role in fibroblast proliferation in oral fibromas.