According to the DAVID analysis, 92 common DEGs of lung cancer and PAH have experimental cancer-related evidence; moreover, there are DEGs related to the positive regulation of transcription, angiogenesis, cell division, growth, adhesion, differentiation, proliferation, migration, senescence, and apoptosis, as well as Wnt, BMP, insulin, metabolic, FoxO, and p53 signaling pathways, and among all of them are twelve of the most frequent TFs (SOX4, TAL1, FOXM1, KLF2, MEIS1, TBX4, EPAS1, ZBTB16, ID4, NR2F1, TFAP2C, and FOXF1). The gene discussed is ID4; the disease is pulmonary arterial hypertension.