Urethan (ethyl carbamate) as a multipotential carcinogen.

Abstract

1. Long-term application of a solution of 20 per cent urethan in acetone was made to the skin of the interscapular area of (C57BL ♀ × C3H ♂)F1, DBA, and C3H mice. This chronic treatment was continued for periods ranging up to 18 months and total amounts of urethan as high as 1800 mg/mouse. 2. Urethan did not evoke skin tumors at the site of application. 3. However, five separate and distinct lesions were induced or potentiated by the long-term application of urethan to the skin of the mice: pulmonary adenomas, mammary carcinomas, malignant mesenchymal tumors in the interscapular fat, cystadenomas of the lacrimal gland, and blood cysts in the liver. 4. Urethan is a multipotential carcinogen.