CDH1 and pulmonary fibrosis: Emerging evidence suggests epithelial to mesenchymal transition (EMT) plays a critical role in the occurrence and progression of pulmonary fibrosis.4,5 During EMT, the epithelial cells lose their tight connection properties and acquire mesenchymal features, which is characterized by the decrease of E-cadherin (E-Cad) in epithelial cells and increased expression of mesenchymal proteins such as α-smooth muscle actin (αSMA).6 EMT is a complex biological process that is regulated by a variety of transcriptional regulators.