To study the clinical significance of the expression of P-glycoprotein(P-gp)in hepatocellular carcinoma(HCC).Methods:Quantitative analysis of P-gp was made by using immunohistochemical method and microimage analysis technique in 47 tumor tissues and 33 tumor-adjacent tissues of the patient with HCC.The biological character was also analyzed.Results:Anti-P-gp immunostaining was observed both in 72 % of cases with tumor tissue and in 66% of cases with adjacent to tumor tissue.When P-gp was detected in HCC

it was mainly localized on the cellular membrane.A significant increase in P-gp level was observed in tumor tissue (P<0.01)and tumor-adjacent tissue(P<0.01)as compared with normal liver tissue.P-gp expression level was significantly higher in HCC of the well differentiated type than in that of poorly differentiated type(P<0.01). HCC with intrahepatic recurrence had a significantly higher P-gp expression level than that without intrahepatic recurrence(P<0.01).P- gp overexpression level correlated well with the invasiveness of HCC(P<0. 05).Conclusion:P-gp expression is Probably a biological marker of Prognostic value to HCC.