Meanwhile, compared with non-smokers, 17 hub genes were identified in differentially expressed mRNAs shared by smokers and COPD patients, including COPS7A, WDTC1, COMMD6, DDB2, INO80E, RUVBL1, COPS5, PTEN, SMAD2, PPARG, CAV1, CTGF, FAU, NHP2, SDAD1, EFTUD1, and DOCK4 (Fig. 1C), which may increase the risk of COPD in people with a history of smoking. The gene discussed is PPARG; the disease is chronic obstructive pulmonary disease.