Evaluation of Immunohistochemical Expression of P53 and Pcna in Pleomorphic Adenoma, Mucoepidermoid and Adenoid Cystic Carcinomas of Salivary Glands

Abstract

Salivary gland tumours are uncommon with a broad heterogeneity. The most common benign tumour is the pleomorphic adenoma, whereas mucoepider moid carcinoma and adenoid cystic carcinoma predominate among the malignancies. The aim of this study was to describe the tissue expression of p53 and PCNA protein in pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma and to compare their expression among the studied tumors. The study enrolled (45)formalin –fixed, paraffin- embedded tissue blocks of salivary gland tumors, diagnosed as pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma (15 cases for each ) and evaluated the immunohistochemical expression of P53 and PCNA proteins. The study revealed positive p53 protein expression in (60%) of muocoepidermoid carcinoma cases and (20%) of adenoid cystic carcinoma cases, while only one case (6.7%) of pleomorphic adenoma was P53 posi tive. The immunopositivity of PCNA protein expression was f ound in (100%) of both mucoepidermoid carcinoma and adenoid cystic carcinoma cases and (66.7%) of pleomorphic adenoma c ases.The results of this study demonstrated that inactivation of p53 protein may play an im portant role in the activation of PCNA with increasing the proliferati on activity of MEC and ACC.