Abstract: ObjectiveTo explore the expression of P-glycoprotein (P-gp), topoisomerase Ⅱ alpha (TopoⅡα), P53 in primary hepatocellular carcinoma (PHC) and their correlations with clinical characteristics. MethodsThe expressions of P-gp, TopoⅡα and P53 were detected by means of SP immunohistochemical technique in 135 cases of PHC. ResultsThe positive rates of P-gp, TopoⅡ α and P53 were 80.74%（109/135）, 46.67%（63/135）, 33.33%（45/135） respectively. The positive rate of P-gp was higher than that of TopoⅡα or P53 (P=0.000). The positive rate of TopoⅡα was higher than that of P53(P＜0.05). The expression of P-gp was related to age, tumor differentiation and tumor size. The expressions of P-gp and TopoⅡα were higher in cases with AFP-elevated than those of AFP-normal (P＜0.05). The expressions of P-gp and P53 were higher in cases with AST-elevated than those of AST-normal (P＜0.05). The expressions of TopoⅡα and P53 weren't related to age, tumor differentiation and tumor size (P＞0.05). The co-expression rate of multidrug resistant genes was 51.85% (70/135). The co-expression rate was higher than individual expression rate (34.07%, χ²=8.706, P＜0.01). ConclusionThe multidrug resistance of PHC is affected by various multidrug resistance genes. There is synergistic effect between single and multiple genes, co-expression of multiple genes mainly. It is important that detection of their expressions may guide the clinical use of drugs and predicate chemotherapy effects.