S100A9 and cholangiocarcinoma: Moreover, S100A9 alone could distinguish non-CCA from normal individuals (73% sensitivity, 88% specificity, AUC = 0.832, YI = 0.6, p < 0.0001) and CA19-9 alone can distinguish CCA from non-CCA patients (70% sensitivity, 83% specificity, AUC = 0.716, YI = 0.5, p = 0.0009) (Table 3).