Prognostic significance of Ku80 in pT2N0M0 esophageal squamous cell carcinoma after Ivor-Lewis esophagectomy

Recent studies have shown that Ku80, a DNA repair protein, was involved in progression of malignant tumors. This study aimed to clarify the clinicopathological significance and prognostic value of Ku80 in pT2N0M0 esophageal squamous cell carcinoma (ESCC). We enrolled 217 patients with pT2N0M0 midthoracic ESCC who had undergone Ivor-Lewis esophagectomy. The expression profile of Ku80 was examined by immunohistochemistry. The results were correlated with the clinicopathological variables, overall survival (OS) and disease-free survival (DFS), in pT2N0M0 ESCC patients. The expression of Ku80 were higher in ESCC tissues than the corresponding health esophageal mucosa ( P < 0.001). Clinically, the Ku80 expression levels were significantly related to tumor size ( P = 0.018), differentiation degree ( P = 0.010), and tumor-node-metastasis (TNM) stage ( P = 0.001). Subsequent multivariate analysis demonstrated that tumor size, differentiation degree, TNM stage, and Ku80 expression were independent prognostic factors for the OS and the DFS of pT2N0M0 ESCC patients. Our data indicated that Ku80 expression level associates with key clinicopathological features and is an independent predictor of the OS and the DFS in pT2N0M0 ESCC patients.