We next created an in vitro trans-intrahepatic biliary epithelial migration model in which HCC cells were placed onto a monolayer of human intrahepatic biliary epithelial cells in the upper compartment of a transwell inset coated with Matrigel matrix with/without CTSB inhibitor, and the lower compartment was loaded with DMEM plus 20% fetal bovine serum (FBS) (Fig. 5g). The gene discussed is CTSB; the disease is hepatocellular carcinoma.