MUC5AC and pancreatic serous cystadenoma: Serum MUC5AC levels gave 60.6% sensitivity and 82.3% specificity at a cut-off of >0.67 ng/mL, while a panel combining PKM2, CYFRA21.1, MUC5AC and GGT was beneficial in differentiating malignant (CC) from benign biliary disease (PSC), warranting validation in a prospective trial [157].