Prognostic Implication of Ezrin Overexpression in Myxofibrosarcomas

The bases of tumorigenesis, progression, and metastasis remain obscure in myxofibrosarcoma. As a member of ezrin-radixin-moesin family, ezrin acts as a link between the cell membrane and actin cytoskeleton to integrate cell adhesion-mediated signaling. It is implicated in tumor progression and metastatic dissemination, and it is associated with adverse outcomes in several cancer types, including pediatric sarcomas. Ezrin immunostain could be assessed from tissue microarrays of 78 cases of primary localized myxofibrosarcomas and correlated with clinicopathological factors and patient survival. In two myxofibrosarcoma cell lines, ezrin mRNA expression was measured by real-time reverse transcriptase-polymerase chain reaction and the endogenous expression and activating phosphorylation of ezrin protein analyzed by Western blot test. Ezrin overexpression was significantly associated with remarkable tumor necrosis (P = 0.025), increased histological grades (P = 0.037), advanced American Joint Committee on Cancer stages (P = 0.034), and higher mitotic rate (P < 0.001). Importantly, ezrin overexpression independently predicted inferior metastasis-free survival (P = 0.012, risk ratio = 4.083) and disease-specific survival (P = 0.0337, risk ratio = 4.537). The mRNA and total protein of ezrin in various cells were comparable in the expression level. Despite variation in abundance, phosphorylated ezrin at threonine(567) was detectable in myxofibrosarcoma cell lines but not in fibroblasts. In primary myxofibrosarcomas, ezrin overexpression correlates with important prognostic elements and independently portends worse outcomes, highlighting the potential prognostic usefulness of ezrin in predicting tumor aggressiveness.