To investigate the potential clinical significance of ESCCAL-1 in ESCC diagnosis, we performed ROC analysis and found that the area under curve (AUC) of ESCCAL-1 in the 6 datasets (GSE120356, GSE53622, TCGA, GSE53624, GSE53625, and our cohort) were 1.0, 0.9378, 0.8264, 0.933, 0.9339, and 0.665 (Supplementary Fig. 1A–F), respectively. This evidence concerns the gene CASC9 and esophageal squamous cell carcinoma.