Although the pathogenesis of cancer of the kidney in man is largely unknown, certain aspects of renal carcinogenesis in experimental animals have now been elucidated.2 Three main agents have been studied—hormones, chemical carcinogens, and viruses—and the present account will be confined to a consideration of these factors.
Spontaneous renal neoplasms are rare in laboratory animals,2 but the incidence may rise as a result of inbreeding, both in mice and in rats. The exact patterns of genetic transmission are obscure, except for the Wistar rats, studied by Eker and Mossige,3 in whom the tumors appeared to be inherited through a single dominant gene which was not sex-linked. The incidence of renal tumors in rats and mice is also increased if animals are exposed to ionizing radiations,4,5 although observations of this kind inevitably beg the general question of "spontaneous" neoplasia.
The carcinogenic effect of estrogens on the kidneys of