The results indicated that the expression levels of E2F1, E2F2, E2F3, E2F5, E2F6, E2F7, and E2F8 were higher in lung adenocarcinoma and squamous cell lung carcinoma tissues than in lung tissues, whereas and the expression level of E2F4 was lower in the former than in the latter (Figure 2). The gene discussed is E2F2; the disease is squamous cell lung carcinoma.