The univariate analysis demonstrated that the high expression levels of MIF (P = 0.012 and P = 0.011) or CXCR4 (P = 0.010 and P = 0.012) in tumor cells were significantly correlated with poor DFS and OS in patients with metastatic/recurrent ESCC (Figure 3) but no association with locoregional ESCC (Data not shown). This evidence concerns the gene CXCR4 and esophageal squamous cell carcinoma.