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 α5 in esophageal squamous cell carcinoma (ESCC) are not clear. Here, by using tissue microarrays and immunohistochemical method, integrin α5 expression was retrospectively evaluated in 147 samples of human ESCC. Results showed that expression of integrin α5 was heterogeneous and varied from negative to intense expression in a membrane and cytoplasmic distribution manner. High expression of integrin α5 was significantly correlated with lymph node metastasis (P = .042) and tumor size (P = .042). Kaplan-Meier analysis revealed that high expression of integrin α5 was related to poor overall survival of ESCC patients (P = .018). Multivariate analysis suggested that integrin α5 expression status was an independent prognostic factor for ESCC (P = .003). Moreover, integrin α5 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 α5 led to decreased growth, migration, and invasion of ESCC cells. Combined, integrin α5 might play important roles in the progression of ESCC. Integrin α5 is a novel biomarker to predict the prognosis of ESCC patients.