ROC curves of COL6A5 and COL18A1 indicated that good predictive performance could only be attained by COL6A5 in TCGA (AUC = 0.679, Fig. S1A), while COL18A1 had no predictive ability (Figs. S1C and S1D), suggesting that a single gene is not suitable for survival prediction of ESCC patients. This evidence concerns the gene COL18A1 and esophageal squamous cell carcinoma.