Significance of the Expression of Tumor Markers in Adenoid Cystic Carcinoma and Pleomorphic Adenoma of the Salivary Gland

Abstract

Background & Objectives: Salivary gland tumors are characterized by extreme histological diversity. Even within a single tumor, various histological patterns are observed. The same histological patterns are shared among various tumor types, regardless of the biological behavior, making diagnosis difficult. Although a great number of immunohistochemical studies of major salivary gland tumors have been published, their clinical and diagnostic implications are not fully apparent. We have performed basic immunohistochemical stains of pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) to determine the diagnostic value of c-kit, Ki-67, glial fibrillary acidic protein (GFAP) and p53.

Materials & Method: Paraffin-embedded tissue specimens from 48 cases, who were diagnosed as PA (n=31) and ACC (n=17) from 1993 to 2002, were immunohistochemically stained for c-kit, Ki-67, GFAP and p53.

Results: In the immunohistochemical stains of c-kit, Ki-67 and p53, there were no difference between PA and ACC. However, in the immunohistochemical stain of GFAP, there were difference in PA and ACC. GFAP was expressed in 74% of the PA and was not expressed in all cases of ACC.

Conclusions: These data suggest that GFAP immunoreactivity could be helped in the occasional differential diagnostic dilemma of pleomorphic adenoma versus adenoid cystic carcinoma in salivary gland.