OCLN and neoplasm: Negative expression of E‐cadherin and a strong positive expression of N‐cadherin, so‐called ‘cadherin switch’ have been reported in undifferentiated tumours and metastases.44, 45 Loss of claudin and occludin which are the integral membrane proteins localized at the epithelial tight junctions further support the induction of EMT upon COSMC deletion in epithelial PDAC cells.