Leukæmogenesis by Urethan in New-born Swiss Mice

Abstract

AFTER earlier evidence that urethan induces or enhances the formation of pulmonary adenomas in rodents^1,2, more recent reports suggest a multi-potential carcinogenic activity of this chemical. Salaman and Roe³ and Graffi et al. ⁴ first demonstrated that urethan initiates skin carcinogenesis although it does not induce skin tumours when administered alone. Tannenbaum and Silverstone⁵, by long-term application of urethan to the skin of inbred mice, observed not only lung adenomas but also tumours of the mammary gland, interscapular fat, and lacrimal glands. Kawamoto et al. ⁶ reported the augmenting influence of urethan on leukæmogenesis induced in low-leukæmic strains of mice by X-rays, oastrogenic hormone or methylcholanthrene. Berenblum and Trainin⁷ showed that urethan treatment following X-irradiation results in a striking increase of leukæmogenesis in C51BL mice.