CDH1 and small cell lung carcinoma: Epithelial‐to‐mesenchymal transition (EMT), which involves a switch in cellular phenotypic characteristics including the loss of cell polarity, the weakening of cellular adhesion and cytoskeleton remodelling, is one of the most important factors that contribute to the aggressive phenotype of SCLC.4 This process is characterized by an increase in E‐cadherin expression and reduction in vimentin expression.