CEACAM5 and cancer: In addition, the measurement of non-specific serum tumor biomarkers [i.e., carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA)] is commonly conducted in order to help in the diagnosis of CCA, but their low sensitivity (particularly in early stages of the disease) and specificity (also elevated in some PSC patients without cancer), raise important concerns regarding their clinical utility [7,10].