Ki-67 and p53 immunostaining assessment of proliferative activity in salivary tumors

Salivary gland tumors are rare neoplasias with approximately 34 different histological types. Because they have a considerably histological and biological behavior variability, salivary gland tumors represent a challenge both for the pathologist and the surgeon regarding their diagnosis, prognosis and treatment. Evaluation of mitotic index in case of Ki-67 and p53 expression has proved to be useful in predicting the biological aggressiveness in many tumors. In this study, we have analyzed the p53 and Ki-67 immunohistochemical expressions in 40 cases of salivary gland tumors, their correlations with clinicopathological factors and the prognostic relevance and diagnostic value of the results obtained. We analyzed eight pleomorphic adenomas (PA), seven Warthin tumors (WT), five basal cell adenomas (BA), four carcinomas ex pleomorphic adenoma (CEPA), four mucoepidermoid carcinomas (MEC), four acinic cell carcinomas (AC), four adenoid cystic carcinomas (ACC) and four adenocarcinomas not otherwise specified (ADK NOS). p53 positive staining was detected in 18 of the 40 cases studied, with higher expression in the malignant salivary tumors investigated. Ki-67 was expressed in 29 cases. High p53 and Ki-67 expression was noted in 3/4 CEPA, 3/4 ADK NOS and 2/4 MEC. Also, 2/8 PA, 3/7 WT and 2/5 BA were p53 positive and 2/7 WT and 2/5 BA had high Ki-67 mitotic index. The investigation of p53 and Ki-67 expression is useful in identifying highly proliferative forms of salivary tumors, with aggressive potential of evolution. The evaluation of these proliferative markers seems to have a prognostic value for CEPA, ADK NOS and MEC types of salivary tumors.