EGFR and chronic obstructive pulmonary disease: In this study, KEGG pathway enrichment analysis showed that the pathways with significant enrichment included TGF-β, PI3K-Akt, ErbB, viral carcinogenesis, non-small cell lung cancer, and the proteoglycan pathway of cancer, etc. Similarly, Liu et al. compared the miRNA expression profiles of COPD patients with healthy controls, and the results showed that miR-23a, miR-25, miR-145, and miR-224 might play important roles in inflammation, oxidative stress, lipid metabolism disorder, cell proliferation, and apoptosis.