Immunohistochemical evaluation of intermediate filament proteins in squamous papilloma and oral verrucous carcinoma

Objective: Cytokeratins (CKs) are the intermediate filament proteins of the epithelium cells, which have become important markers of normal and abnormal cell differentiation. The goal of the present study was to investigate the expression pattern of CK 10, 13, 14 and 16 in oral verrucous carcinoma (OVC) and oral squamous papilloma (OSP). Material and Methods: Formalin-fixed paraffin-embedded sections from eight cases of each lesion were assessed. Immunohistochemistry was carried out using streptoavidin-biotin complex method. Results: In OVC, CK 10 was expressed in suprabasal to superficial layers whereas in OSP mainly in superficial layer. CK 13 was detected in prickle and superficial cells in most cases of OVC and in suprabasal to superficial cells of OSP. All the cell layers of OVC reacted positively for CK 14 while basal and suprabasal layers of OSP were more pronounced for CK 14. Finally, CK 16 was observed in suprabasal to superficial layer in OVC and the majority cases in OSP showed only superficial reactive cells. Conclusions: CK 10, 13, 14 and 16 immunohistochemical profile emphasis the biological behavior of the studied lesions and confirm the use of these proteins as markers of differentiation.