GGT1 and cholangiocarcinoma: Moreover, the high levels of exosomal pantetheinase (VNN1), C-reactive protein (CRP), fibrinogen gamma chain (FIBG), immunoglobulin heavy constant alpha 1 (IGHA1), alpha-1-acid glycoprotein 1 (A1AG1), and gamma-glutamyltransferase 1 (GGT1) in CCA might benefit the differential diagnosis of intrahepatic CCA (iCCA) versus HCC [67].