E2F1 and hepatocellular carcinoma: Consistent with the results of the GEO database, the protein levels of CENPA, E2F1, FOXM1, HMGA1, HMGB2 and MYBL2 in HCC tissues were increased (Fig. 8A), and only the protein expression of ESR1 in HCC tissues was decreased (Additional file 7: Fig. S7A).