By our calculation, serum clusterin had an optimal diagnostic cut-off point (serum clusterin concentration = 335.5 μg/mL) for esophageal squamous cell carcinoma with sensitivity of 71.26% (95% CI, 60.57% to 80.46%) and specificity of 77.94% (95% CI, 70.03% to 84.59%). This evidence concerns the gene CLU and esophageal squamous cell carcinoma.