S100A9 and cholangiocarcinoma: The best model for diagnosis of non-CCA from the normal group was provided by the combination of five biomarkers (S100A9, MUC5AC, TGF-β1, angiopoietin-2, and CA19-9) which generated the highest AUC value (0.911) at a sensitivity and specificity of 82.5% and 85%, respectively.