Immunocytochemical localization of ferritin in the kidney and renal tumours

The distribution of ferritin in the kidney and renal tumors was studied using a polyclonal anti-ferritin antiserum and immunocytochemical techniques. Ten fetal kidneys, 5 adult kidneys and 56 renal tumours were studied. Ferritin first appears in the maturing fetal nephron where it is confined to the proximal tubule. In the adult kidney ferritin is also restricted to the proximal tubule. Ferritin was not seen in 18 nephroblastomas nor in 4 renal sarcomas, but 14 of 26 renal cell carcinomas and 5 of 8 renal oncocytomas contained ferritin. The relationship between the expression of ferritin and tumour differentiation is discussed.