Concomitant expression of ezrin and HER2 predicts distant metastasis and poor prognosis of patients with salivary gland carcinomas

Abstract

Salivary gland carcinomas (SGCs) exhibit heterogeneous biological behaviors, including the formation of distant metastases, which is a critical event associated with poor prognosis. Ezrin, which is a member of the ezrin-radixin-moesin family of plasma membrane-cytoskeleton linker proteins, may provide a marker for metastasis and poor survival of patients with cancer. The aim of the present study was to investigate the relationship between ezrin expression and the expression of HER2, p53, and Ki-67 as well as clinicopathological factors in SGCs. For this purpose, we used immunohistochemistry to analyze the expression of these proteins in tissue microarrays prepared from formalin-fixed, paraffin-embedded primary tumor tissues of 221 patients with SGCs. Using receiver operating characteristic curves, we determined cut-off values of 30% and 5.0% for high expression of ezrin and Ki-67, respectively. High ezrin expression detected in samples from 63 (28.5%) patients with SGCs significantly correlated with male sex, high-grade histopathology, high Ki-67 labeling index, HER2 overexpression, aberrant expression of p53, and distant metastasis. Multivariate analysis demonstrated that high ezrin expression was an independent prognostic factor for shorter overall survival (hazard ratio, 2.11 [1.09-4.05]; P=.027). Furthermore, concomitant high expression of ezrin and HER2 overexpression correlated significantly with shorter disease-free survival and overall survival as well as a high incidence of distant metastasis (P<.001). These findings indicate that ezrin and HER2 expression in patients with SGCs represents a high-grade histopathological subtype that requires adjuvant therapy, including molecularly targeted therapies, to decrease the risk of subsequent metastasis.