The extent of senescent BECs in small bile ducts and bile ductules was closely related to stage and activity of PBC and the increased expression of p16 <sup>INK4a</sup> in bile ductules was correlated with inadequate response to UDCA.
PATIENTS/SUBJECTS/METHODS: The methylation status of p16 was evaluated in 22 HCC, 17 cirrhosis, 17 chronic hepatitis, nine primary biliary cirrhosis (PBC), eight autoimmune hepatitis, seven drug induced liver disease, six fatty liver, and three normal liver tissues using methylation specific polymerase chain reaction (MSP). p16 protein expression was also examined by immunohistochemical staining.