Usefulness of bile as a biomarker via ferroptosis and cysteine prenylation in cholangiocarcinoma; role of diagnosis and differentiation from benign biliary disease

•Iron metabolism is dysregulated in extrahepatic cholangiocarcinoma (eCCA).•Redox-dependent modification of cysteine has crucial role in eCCA.•Proteins related to Ferroptosis and cysteine modification are seen in bile fluids.•Bile fluids have a role for differentiation of eCCA from benign biliary stricture.