Expression of Eps8 correlates with poor survival in oral squamous cell carcinoma

Aims: Epidermal growth factor receptor pathway substrate 8 (Eps8) is a signaling protein implicated in the development of many human cancers including oral squamous cell carcinoma (OSCC). This study examined the expression of Eps8 and assessed its significance in patients with OSCC. Methods: Immunohistochemical staining for Eps8 was conducted in 205 cases of OSCC collected over 7 years. The results were analyzed and correlated with patients' clinical outcomes. Results: We identified Eps8 expression in 186 of the 205 cases of OSCC (91%) and the aberrance occurred primarily in the cytoplasm of OSCC cells. Univariate analysis revealed that patients with Eps8 expression had significantly poorer 5-year overall survival (OS) than those without it (43% vs 74%, P=0.014). Eps8 expression was also identified as an independent predictive factor for poorer OS by a multivariate analysis in regression modeling (P=0.021, HR=2.7). A Kaplan-Meier analysis showed that patients with positive Eps8 expression had a significantly poorer OS than patients with negative/low Eps8 expression (P=0.038). The difference in disease-free survival between positive Eps8 expression and negative/low Eps8 expression nearly reached statistical significance (P=0.051). Conclusion: Eps8 is frequently expressed in OSCC. The aberrant expression of Eps8 closely correlated with poor survival in patients with OSCC.