SDF-1α predicts poor prognosis in patients with locally advanced esophageal squamous cell carcinoma receiving definitive concurrent chemoradiotherapy

Background: Stromal cell-derived factor-1α (SDF-1α) is a chemokine associated with tumor progression in various types of cancers. The current study aimed to evaluate whether pre-treatment or kinetics of SDF-1α can predict the prognosis in patients with esophageal squamous cell carcinoma (ESCC) receiving definitive concurrent chemoradiotherapy (CCRT). Methods: A total of 97 patients with ESCC were identified at Kaohsiung Chang Gung Memorial Hospital between January 2010 and December 2015. Serum concentration of SDF-1α was measured at day 0 (pre-treatment) and chemotherapy day 28 to determine its kinetics and the cut-off level of pre-chemotherapy SDF-1α was 1.5 ng/mL. Two ESCC cell lines, TE1 and KYSE30, were selected to evaluate the function of SDF-1α. Results: Univariate and multivariate analyses showed that pre-treatment SDF-1α ≥ 1.5 ng/mL and an increased SDF-1α level after treatment were significantly associated with worse progression-free survival (p = 0.021 and p = 0.008, respectively) and overall survival (p = 0.005 and p < 0.001, respectively). In addition, patients with pre-treatment SDF-1α ≥ 1.5 ng/mL and increased SDF-1α levels after treatment were found to have poor response to CCRT. Moreover, these cell lines were treated with chemotherapeutic agents (cisplatin or 5-FU) and SDF-1α, alone or in combination. Our in vitro study results showed SDF-1α promoted the proliferation of tumor cells and overcame the cytotoxic effect of chemotherapy (p < 0.001). Conclusion: Our study suggested that SDF-1α plays an important role in ESCC disease progression and that pre-treatment SDF-1α level and kinetics of SDF-1α are the independent prognostic factors for ESCC patients receiving definitive CCRT. Periodic determinations of serum SDF-1α level may be valuable to predict prognosis of ESCC in clinical practice.