Liver biopsies from PBC patients and controls (normal liver, primary sclerosing cholangitis and alcoholic cirrhosis) were immunohistochemically examined for oestrogen receptor alpha (OR-α), oestrogen receptor beta (OR-β), cytokeratin 19, proliferating cellular nuclear antigen (PCNA), and Fas by terminal deoxynucleotide transferase end labelling (TUNEL) [174]. Here, FAS is linked to primary biliary cholangitis.