For comparison, the top 50 of SDNs, DEPs and DEGs in terms of statistical P value were selected as potential signature molecules for building ESCC-related classifiers and the overlap between these molecules is rather small, i.e. four present (PPP2R1A, RPS15A, RPLP2 and RPSA) in SDNs and DEPs, one (RUVBL1) present in SDNs and DEGs, non-overlap between DEPs and DEGs (Table 2). This evidence concerns the gene PPP2R1A and esophageal squamous cell carcinoma.