4.According to above basic findings, it is important to confirm those results in clinic. In this branch, the investigators will use the patient control analgesic (PCA) device to investigate the consumption of morphine for patients undergoing hepatic surgery. Preoperative and postoperative blood will be sampling and tinny liver tissue (10mm3) will be harvested to correlate their morphine consumption and pain questionnaire will be evaluated for their pain control quality. Certainly, the morphine consumption will be correlated with the molecule amount to figure out possible relationship between morphine consumption and those molecules.