We previously found that siRNA against human antigen R prevented the CS-induced downregulation of E-cadherin and upregulation of vimentin and zinc finger E-box binding homeobox 1 (ZEB1) in AECs in vitro [26], suggesting that human antigen R partially enhances the EMT and post-transcriptionally regulates the airway epithelium in COPD. This evidence concerns the gene CDH1 and chronic obstructive pulmonary disease.