ROC analysis revealed that S100A9, MUC5AC, TGF-β1, or CA19-9 individually can effectively distinguish CCA patients from the normal group (73–78% sensitivity, 58–98% specificity, AUC = 0.639–0.888, YI = 0.3–0.7, p < 0.05). Here, S100A9 is linked to cholangiocarcinoma.