Interestingly, the intensity of cathepsin Z staining in hepatocytes increased with progression of PBC (Fig. 3Ad–f), which was also shown by immunohistochemical scoring (jaundice-stage v.s early-stage, P = 4.9 × 10−5, jaundice-stage v.s late-stage, P = 4.7 × 10−3) (Fig. 3B). This evidence concerns the gene CTSZ and primary biliary cholangitis.