Zeng et al. found that the expression of MBD2 was reduced in the airway epithelium of patients with COPD, while in human bronchial epithelial cells, this reduced expression was related to increases in IL-6 and IL-8 mediated by the extracellular signal-regulated kinase and p38 mitogen-activated protein kinase pathways (42). This evidence concerns the gene MAPK14 and chronic obstructive pulmonary disease.