The western blotting assay showed that the WWP1 protein level of the normal human intrahepatic biliary epithelial cell (HIBEC) was significantly lower than that of the four ICC cell lines (HCCC-9810, RBE, HuCCT1, and Huh28), while among the four ICC cell lines, the HuCCT1 cell line had the highest endogenous WWP1 expression, and the other three cell lines had relatively lower endogenous WWP1 expression levels (Fig. 2A). This evidence concerns the gene WWP1 and intrahepatic cholangiocarcinoma.