CDH1 and cholangiocarcinoma: The activation of TGF‐β signalling decreases epithelial cadherin (E‐cadherin) and increases neural cadherin (N‐cadherin) through epithelial‐to‐mesenchymal transition (EMT) to promote the metastasis, invasion, and progression of CCA and other tumours.48, 49, 50 Blocking the TGF‐β signal pathway can promote the apoptosis of the CCA cells, which makes targeting the TGF‐β signal pathway has potential effect on the treatment of CCA.51 However, David et al.