We then used the Wilcoxon rank sum test to compare the level of expression of the 12 CRGs (ATP7B, CDKN2A, DLAT, DLD, FDX1, GLS, LIAS, LIPT1, MTF1, PDHA1, PDHB, SLC31A1) between cluster 1 and 2 from the TCGA-ESCC cohort, and the results are shown in Figure 3E. This evidence concerns the gene CDKN2A and esophageal squamous cell carcinoma.