Immunohistochemical Analysis of p63 Marker Expression in Pleomorphic Adenoma and Mucoepidermoid Carcinoma of Salivary Gland

Tumors of salivary gland represent 2-3% of head and neck neoplasms and little is known about the underlying molecular mechanisms leading to tumorigenesis. P63 plays an essential role in epithelial development، stem cell identity and cellular differentiation and may act as an oncogene. The expression of P63 was analyzed to investigate the role of this marker in tumorigenesis of salivary gland neoplasms. Subjects and In this study، tissue specimens of 18 pleomorphic denoma (PA) and 9 mucoepidermoid carcinoma (MEC) were examined by immunohistochemistry for p63 expression. The percentage of positive neoplastic cells was calculated from a minimum of 1000 cells. In normal salivary gland and PA، P63 was expressed in myoepithelial and basal duct cells، whereas ductal and acinus cells were always negative. In MEC، intermediate and epidermoid cells expressed p63، in contrast to mucous cells. After using statistical test، the percentage of p63 positive cells in MEC was 84. 44% and in PA was 57. 83% (p<0. 05). p63 is expressed in the nuclei of normal salivary gland myoepithelial and basal cells. P63 expression is retained in the epidermoid cells of MEC and myoepithelial and basal cells of PA، which suggests a role of p63 in oncogenesis of these tumors.