The expression patterns were visually represented in heatmaps, histograms and box diagrams, revealing that many methylation regulators, including METTL3, RBM15, RNM15B, CBLL1, YTHDC2, YTHDF1, YTHDF2, HNNRPC, LPPPRC, RBMX, FTO and ALKBH5, were significantly overexpressed in COPD patients, whereas WTAP, YTHDC1 and HNRNPA2B1 showed reduced expression levels in these patients (Figure 1A–C). Here, YTHDC2 is linked to chronic obstructive pulmonary disease.