The common connection patterns (CCPs) formed between the most frequent LC DEGs co-expressed in LC and PAH suggest that there is an important group of genes and TFs (FOXM1 and FOXF1) that act as a group in all types and subtypes of lung cancer during the acquisition of the hallmarks of cancer, while others (TCF21, SOX17, TAL1, LMO2, KLF2, and TBX4) are important during lung cancer progression. The gene discussed is TCF21; the disease is pulmonary arterial hypertension.