In the present study, considering that ADRB2 is an asthma susceptibility gene and E2F1 is closely related to the occurrence of lung cancer and other diseases, we performed a dual-luciferase reporter gene assay in two different cell lines—A549 (human pulmonary adenocarcinoma cell) and BEAS-2B (transformed human bronchiolar epithelial cell), verifying that the transcription factor E2F1 served as a transcriptional activator of the human ADRB2 gene by binding to its promoter. The gene discussed is E2F1; the disease is lung cancer.