Expression of GP160 mRNA in renal cell carcinoma: an attempt to predict the sensitivity of IFN-alpha therapy

Abstract

Alpha-interferon (IFN-alpha) has significant antitumor activity against advanced renal cell carcinoma (RC). Although numerous clinical trials reported major responses in approximately 15% of patients subjected to INF-alpha therapy, it has been impossible to predict which patients will respond to IFN-alpha. RC cell lines could be subdivided into those that are inhibited by IFN-alpha and those that are not. The expression of GP160 (Aminopeptidase a/kidney-associated differentiation antigens) correlated with resistance to IFN-alpha. In RC xenografts using a mouse model, though GP160(+) RC cell lines were resistant to IFN-alpha, GP160(-) RC cell lines were markedly sensitive to IFN-alpha. In this study, we assayed 26 RC patients for the expression of GP160 in mRNA level using RT-PCR (reverse transcription polymerase chain reaction). In 23 (88.5%) patients GP160 mRNA expression are remarkable as in normal kidney tissue, but in 2 (7.7%) patients, GP160 mRNA expression was weak. And in 1 (3.8%) patient, GP160 mRNA expression was hardly detectable, and in this patient complete remission was achieved with IFN-alpha therapy for advanced lung and mediastinal metastatic RC.