TNF and chronic obstructive pulmonary disease: KEGG results showed that these differentially methylated mRNAs were significantly enriched in interleukin (IL)-17 signaling pathway, tumor necrosis factor (TNF) signaling pathway, natural killer cell-induced cytotoxicity, nuclear factor kappa B (NF-κB) signaling pathway, and other aspects, suggesting that m6A methylation may have an immunomodulatory effect in COPD (Figure 8D).