The mean YKL-40 level was 97.27 ng/ml (range, 6.95-502.10) in patients with ESCC, 57.97 ng/ml (range, 1.21-429.30) in patients with benign esophageal diseases, 23.89 ng/ml (range, 2.56-132.26) in healthy controls and 97.27 ng/ml (range, 6.95-430.80) in early stage ESCC. This evidence concerns the gene CHI3L1 and esophageal squamous cell carcinoma.