CDH2 and chronic obstructive pulmonary disease: The airway epithelium from COPD patient exhibits persistent activation of EMT, with decreased protein levels of epithelial markers such as E-cadherin and zona occludence-1 (ZO-1) and increased protein levels of mesenchymal markers, including N-cadherin, vimentin, and α-smooth muscle actin (α-SMA) [10–12].