Prognostic Impact of the Enhancer of Zeste Homolog 2 Overexpression in Node-Positive Laryngeal Cancer

초록

Background: Epithelial mesenchymal transition (EMT) has an important role in invasion and metastasis of tumor cells. EZH2 overexpression is also commonly associated with poor prognosis in a variety of tumor types. However, the exact role of EZH2 and its clinical significance in laryngeal cancer are not yet known. The purpose of this study is to evaluate the roles of EZH2 and other EMT associated proteins on progression and metastasis in locally advanced node-positive laryngeal cancer. Methods: We analyzed the significance of these EMT associated protein expression in curatively resected (R0) laryngeal cancer patient as a prognostic marker. Total twenty-nine consecutive patients were included in our study. We used protein immunohistochemistry to evaluate EZH2, vimentin, E-cadherin expression on tissue microarray in duplicate. Also we retrospectively reviewed all medical records and tried to analyze the relationship between the expression of EMT markers and prognosis. The relationship between these protein expressions and survival was plotted on a Kaplan-Meier curve. Results: EZH2 was expressed in 11 patients (37.9%). Recurrence rate was significantly higher in patients with positive EZH2 expression than that of patients with no expression (recurrence rate, 72.7% vs 33.3%; p=0.039). Patients with a positive EZH2 expression showed a tendency of shorter their disease progression free survival (median progression free survival [PFS], 11.8 months) than did the patients without expression (median PFS, 23.9 months). However there was no statistical significance (p= 0.0892). Conclusions: EZH2 overexpression showed a close correlation in recurrence rate and relapse free survival. Our findings suggest an important role of EZH2 in progression of laryngeal cancer. Key Words: Epithelial-mesenchymal transition; EZH2; Immunohistochemistry