AIM:To evaluate the possibility of using insulin as a carrierfor carcinoma-targeted therapy mediated by receptor,andto investigate the expression of insulin receptor in humanhepatocellular carcinoma and the receptor bindingcharacteristics of insulin-IUdR (iododeoxyuridine).METHODS:IUdR was covalently conjugated to insulin.Receptor binding assays of ~(125)I-insulin to human hepatocellularcarcinoma and its adjacent tissue were performed.Competitive displacements of ~(125)I-insulin by insulin andinsulin-IUdR to bind to insulin receptor were respectivelycarried out.Statistical comparisons between the means weremade with paired t-test at a confidence level of 95 %.RESULTS:The data indicated that there were high-andlow-affinity binding sites for ~(125)I-insulin on both hepatocellularcarcinoma and its adjacent tissue.Hepatocellular carcinomahad a significantly higher Bmax for high affinity binding sitethan its adjacent liver tissue (P<0.05,t=2.275).Insulin-IUdRcompeted as effectively as insulin with ~(125)I-insulin for bindingto insulin receptor.Values of IC_(50)1,C_(50)2,KI1 and KI2 forinsulin-IUdR were 11.50±2.83 nmol·L~(-1),19.35±5.11 nmol·L~(-1),11.26±2.65 nmol·L~(-1) and 19.30±5.02 nmol·L~(-1) respectively,andfor insulin were 5.01±1.24 nmol·L~(-1),17.75±4.86 nmol·L~(-1),4.85±1.12 nmol·L~(-1) and 17.69±4.81 nmol·L~(-1),respectively.Values of IC_(50)1 and KI1 for insulin-IUdR were significantlyhigher than that for insulin (P<0.01,t=4.537 and 4.813).CONCLUSION: It is possible to use insulin as a carrier for carcinoma-targeted therapy mediated by receptor. AIM: To evaluate the possibility of using insulin as a carrier for carcinoma-targeted therapy mediated by receptor, and investigate the expression of insulin receptor in human hepatocellular carcinoma and the receptor binding specificity of insulin-IUdR (iododeoxyuridine). METHODS: IUdR was covalently conjugated to insulin . Receptor binding assays of ~ (125) I-insulin to human hepatocellularcarcinoma and its adjacent tissue were performed. Competent displacements of ~ (125) I-insulin by insulin and insulin-IUdR to bind to insulin receptor were respectively captured out. Statistical comparisons between the means 95%. RESULTS: The data indicated that there were high-andlow-affinity binding sites for ~ (125) I-insulin on both hepatocellular carcinoma and its adjacent tissues. higher Bmax for high affinity binding sitethan its adjacent liver tissue (P <0.05, t = 2.275) .Insulin-IUdRcompeted as effectively as insul (50) 1, C_ (50) 2, KI1 and KI2 forinsulin-IUdR were 11.50 ± 2.83 nmol·L -1, 19.35 ± 5.11 andfor insulin were 5.01 ± 1.24 nmol·L -1, 17.75 ± 2.65 nmol·L -1 and 19.30 ± 5.02 nmol·L -1, respectively ± 4.86 nmol·L -1, 4.85 ± 1.12 nmol·L -1 and 17.69 ± 4.81 nmol·L -1, respectively.Values ​​of IC 50 and KI 1 for insulin-IUdR were significantlyhigher than that for insulin (P <0.01, t = 4.537 and 4.813). CONCLUSION: It is possible to use insulin as a carrier for carcinoma-targeted therapy mediated by receptor.