E2F1 is overregulated in seven lung cancer datasets and is related to: 1) HPV infection; 2) HBV and EBV virus infection along with E2F3; 3) the cell cycle and pathways in cancer along with E2F3; and 4) HTVL-I infection along with E2F3 and TCF3. The gene discussed is TCF3; the disease is lung cancer.