Osteopontin Expression Is Associated with the Poor Prognosis in Patients with Locally Advanced Esophageal Squamous Cell Carcinoma Receiving Preoperative Chemoradiotherapy

Background. The osteopontin has been involved in therapeutic resistance in a variety of cancers. But, the significance of osteopontin expression on the prognosis of patients with locally advanced esophageal squamous cell carcinoma (ESCC) receiving chemoradiotherapy is unclear. Methods. In 80 patients with locally advanced ESCC receiving preoperative chemoradiotherapy between 1999 and 2012, osteopontin expression was evaluated by immunohistochemistry and correlated with treatment outcome. The functional role of osteopontin in ESCC cell lines was determined by osteopontin-mediated siRNA. Results. Osteopontin expression and clinical T4 classification were significantly associated with poor pathological complete response. Univariate analyses demonstrated that osteopontin overexpression and clinical T classification, T4, were significantly associated with worse overall survival and disease-free survival. In multivariate comparison, osteopontin overexpression and clinical T classification, T4, represented the independent adverse prognosticator. In ESCC cell lines, endogenous osteopontin depletion by osteopontin-mediated siRNA increased sensitivity to cisplatin. Osteopontin expression is independently correlated with the response of chemoradiotherapy and prognosis of patients with locally advanced ESCC receiving preoperative chemoradiotherapy. Conclusions. Our results suggest that osteopontin may be a potential therapeutic target for patients with ESCC treated with preoperative chemoradiotherapy.