FCN2 and cholangiocarcinoma: EV-related proteins including FIBG, serum amyloid P-component (SAMP), ficolin-2 (FCN2), and plasma protease C1 inhibitor (IC1), as well as inter-alpha-trypsin inhibitor heavy chain H4 (ITIH4), are found highly expressed in CCA patients in stages I–II, in comparison to PSC patients, whereas high levels of EV-FCN2 and IC1 have an increased diagnostic value, compared to serum CA-19-9 in CCA patients in stages I–II [67,105].