Mirroring their previous results on XPO1, they demonstrated that CDC7 expression increased progressively from LUAD → T-LUAD → T-SCLC → SCLC in patient tumors, with CDC7 transcription induced following RB1 and p53 loss in adenocarcinoma cell lines, likely through direct regulation by p53 and E2F1 [57]. This evidence concerns the gene E2F1 and small cell lung carcinoma.