E2F1 and lung cancer: As the expression of E2F1 was markedly regulated by GCN5 at both protein and mRNA levels in E7‐expressing cells (Figure 3B,C) and GCN5 was shown to bind E2F1 promoter in lung cancer cell lines,22 we believe that GCN5 binds E2F1 promoter in E7‐expressing cells.