Sensitivity to carcinogenesis in nude mice: skin tumors caused by transplacental exposure to ethylnitrosourea.

Female athymic nude mice and their phenotypically normal littermates were exposed transplacentally to ethylnitrosourea. Skin tumors (papillomas and sebaceous adenomas) developed on the nude mice with an almost tenfold greater incidence than on their haired littermates. Skin tumors were also induced on nude mice but not haired controls by direct intraperitoneal treatment with ethylnitrosourea. These results indicate that nude mice have higher than normal susceptibility to carcinogenesis under some circumstances.