DEMONSTRATION OF RENIN GENE-EXPRESSION IN NEPHROBLASTOMA BY IN-SITU HYBRIDIZATION

Most patients with nephroblastoma have high levels of plasma renin and some are hypertensive. Blood pressure falls after removal of the affe cted kidney, suggesting that nephroblastoma is associated with renin p roduction either by the tumour or by the kidney. In this study, direct evidence was sought of renin gene expression in nephroblastoma using in situ hybridization. Digoxigenin-labelled riboprobes and an immunope roxidase technique were used to detect cells containing renin mRNA: th is showed renin gene expression in 9 out of 12 cases. There were posit ive cells within metanephric blastema and in occasional neoplastic glo meruloid structures, confirming that in seven cases nephroblastoma tum our cells expressed the renin gene. However, renin gene expression was also demonstrated in perivascular cells of uncertain lineage in seven cases; in five cases there was evidence of renin gene expression in b oth tumour cells and perivascular cells. The latter finding raises the possibility that some of the cells expressing the renin gene could be stromal cells. It is concluded that nephroblastomas contain cells tha t express the renin gene and that some are tumour cells, while other p erivascular cells may be stromal cells.