Epigenomic studies have identified methylation patterns specific to COPD (e.g., C10orf11 in lung), asthma (e.g., IL13, RUNX3, TIGIT in PBMCs) and IPF (e.g., CASZ1 in lung), although much work remains to characterize cell-specific changes and include more ARDS and PAH samples. This evidence concerns the gene RUNX3 and chronic obstructive pulmonary disease.