Immunocytochemistry of renin in renal tumours.

We used a panel of two polyclonal antisera and two monoclonal antibodies to human renin to assess the tissue distribution of immunoreactive renin in a range of tumours and normal human tissues. The only tissue showing positive staining for renin was kidney and all four antisera stained the myoepithelioid cells in the renal cortex. In the survey of tumours we found immunoreactive renin only in renal tumours, namely, renal cell carcinoma, and nephroblastoma (Wilms' tumour). The renin-positive cells were sparse and distributed mainly along the course of the tumour blood vessels. They stained positively with all four antibodies and, in pairs of serial sections, we showed that the same cell reacted with two different antisera. This suggests that renal cell carcinoma and nephroblastoma have within them cells which contain renin.