As displayed in Supplementary Fig. S2, five transcription factors (CREB1, CTCF, YY1, E2F1, MYBL2) were significantly elevated with tumor progression in HCC, indicating that these potential transcription factors may be responsible for the upregulation of H3–H4 histone chaperones in HCC. This evidence concerns the gene E2F1 and hepatocellular carcinoma.