Mechanisms of drug resistance of primary renal cell carcinomas and their clinical significance

OBJECTIVE: By multifactorial analysis, to study the mechanisms of drug resistance of primary renal cell carcinomas (RCC). METHODS: Seventy cases of paraffin-embedded RCC tissue sections were examined for the expression of P-gp, GST-pi and Topo II by immunohistochemical staining. RESULTS: There was 65.7% of RCC with expressed P-gp. Its Expression was stronger in late than in early stage of RCC. GST-pi was expressed in 41.1% RCC, but the magnitude of expression did not correlate with differentiation, type and stage of RCC. All the RCC examined had Topo II expression. Its expression level was lower than that of cancer of the intestine and lung. Among the 70 cases of RCC, 31.4% of them expressed at least one of the 3 drug-resistance parameters. Co-expression of two drug-resistance parameters was observed in 42.8% of the cases that of 3 drug-resistauce parameters in 22.9% of the cases. CONCLUSION: Drug resistance is of common occurrence in RCC. To achieve better therapeutic efficacy, appropriate chemotherapeutic agents should be given to patients with low expression of P-gp and GST-pi but high expression of Topo II.