KRT19 and intrahepatic cholangiocarcinoma: Discrepancies between the findings for DTCs and CTCs may be explained either by differences in the methodology of detection (RT–PCR for CK-19 only, as compared with ICC for CK8, 18 and 19 for the DTCs and Ep-CAM enrichment, followed by pan-cytokeratin staining for CTCs), or because DTCs and CTCs represent two different levels of risk.