Second, regulatory pathways predicted based on the top genes coexpressed with PSMG4 suggested that the top three most significant pathways included “Statin action on the PI3K Akt pathway in COPD”, “DNA damage_Classical NHE mechanism of DSBs repair”, and “Folic acid metabolism”, which may partly explain why PSMG4 plays a key role in LUAD. Here, PIK3CA is linked to chronic obstructive pulmonary disease.