MIIP expression predicts outcomes of surgically resected esophageal squamous cell carcinomas

The migration and invasion inhibitory protein (MIIP) was shown to function as a tumor suppressor gene in gliomas by inhibiting tumor cell growth, migration, and invasion. However, its role and clinical significance in esophageal squamous cell carcinoma (ESCC) have not been elucidated. We investigated the correlation of MIIP expression and clinical outcome in a group of surgically resected ESCCs. Tissue microarrays constructed of 253 surgically resected ESCC primary tumors and paired paracancerous normal esophageal epithelia were used for MIIP evaluation by immunohistochemistry. The clinical and prognostic significance of MIIP expression was analyzed statistically. The expression of MIIP expression in cancer tissues was increased significantly in comparison with the paired paracancerous normal epithelia (P < 0.001). And, MIIP expression was associated with ESCC cells' differentiation (P < 0.001). By Kaplan-Meier analysis, patients with low MIIP expression exhibited significantly improved overall survival (OS, P = 0.039) and a tendency of improved disease-free survival (DFS, P = 0.086) than those with high MIIP expression. In addition, MIIP expression could distinguish OS or DFS of patients with tumors in stage T3-4 (P = 0.020, 0.028), N0 (P = 0.008, 0.032), and stage II (P = 0.004, 0.019), as well as at lower thoracic esophagus (P = 0.024, 0.090). Multivariate analysis showed that MIIP expression was an independent prognostic factor in ESCC OS and DFS. In conclusion, MIIP expressed higher in ESCCs than in paracancerous normal esophageal epithelia and was a positive, independent prognostic factor in resected ESCCs.