MUC16 and cancer: Figure 4 shows one case of distal cholangiocarcinoma. It was difficult for us to know whether the cancer infiltrated the surrounding tissue by preoperative imaging. However, the CA19-9, CA125, and CEA of the patient were lower than the cut-off point in our study. Then radical resection was performed successfully with a negative postoperative pathological margin. Figures 5 and 6 show one case of hilar cholangiocarcinoma and one case of intrahepatic cholangiocarcinoma.