ZEB1 and cholangiocarcinoma: Activation of ZEB1 or Snail leads to an increase in PDL1 expression (41); thirdly, in patients with cholangiocarcinoma, high expression of EMT markers, such as ZEB1, N-cadherin, and Vimentin, along with low expression of E-cadherin, are associated with increased PDL1 expression (42); lastly, similar results are observed in esophageal squamous cell carcinoma, patients with elevated levels of EMT marker ZEB1 and positive PDL1 have the worst prognosis (43).