CXCR4 and esophageal squamous cell carcinoma: The expression of CXCR4 in tumor cells was positively associated with tumor status (P = 0.045) and clinical stage (P = 0.044); whereas the expression of CXCR4 in tumor-infiltrating lymphocytes (TILs) and the expression of MIF in tumor cells and in TILs were not associated with clinical parameters of ESCC patients.