Two of the most frequently dysregulated transcription factors are co-expressed in lung cancer and PAH (FOXM1 and FOXF1), while the other six frequently deregulated transcription factors are co-expressed only in lung cancer (TCF21, SOX17, TAL1, LMO2, KLF2, and TBX4). This evidence concerns the gene TCF21 and pulmonary arterial hypertension.