AMBP and cholangiocarcinoma: To address whether these candidate CCA markers could be combined to build a multiplex assay, pairwise scatter plots of all combinations of plasma S100A9, AACT, AFM, TAOK3, NGAL, PSMA3, and AMBP proteins evaluated their composite effects on the separation of the CCA vs. non-CCA (collapsing normal and DC) groups (Figure 4).