Integrin α5 promotes tumor progression and is an independent unfavorable prognostic factor in esophageal squamous cell carcinoma

The integrin family plays a major role in complex biological events such as differentiation, development, wound healing, and the altered adhesive and invasive properties of tumor cells. The expression and function of integrin alpha 5 in esophageal squamous cell carcinoma (ESCC) are not clear. Here, by using tissue microarrays and immunohistochemical method, integrin alpha 5 expression was retrospectively evaluated in 147 samples of human ESCC. Results showed that expression of integrin alpha 5 was heterogeneous and varied from negative to intense expression in a membrane and cytoplasmic distribution manner. High expression of integrin alpha 5 was significantly correlated with lymph node metastasis (P=.042) and tumor size (P=.042). Kaplan-Meier analysis revealed that high expression of integrin alpha 5 was related to poor overall survival of ESCC patients (P=.018). Multivariate analysis suggested that integrin alpha 5 expression status was an independent prognostic factor for ESCC (P=.003). Moreover, integrin alpha 5 expression was associated with the survival of patients with lymph node metastasis (P=.020), but did not influence the survival of patients without lymph node metastasis. Finally, we found that RNAi-mediated knockdown of integrin alpha 5 led to decreased growth, migration, and invasion of ESCC cells. Combined, integrin alpha 5 might play important roles in the progression of ESCC. Integrin alpha 5 is a novel biomarker to predict the prognosis of ESCC patients. (C) 2015 Elsevier Inc. All rights reserved.