The multipotential carcinogenic action of N-ethyl-N-nitrosourea administered neonatally to mice.

Newborn A, C57BL, DBAf and IF mice were injected s.c. with a range of doses of N-ethyl-N-nitrosourea (ENU). A high proportion of treated mice developed tumours, particularly hepatomata, pulmonary adenomata and carcinomata, and malignant lymphomata of thymus and spleen. Liver tumours occurred most frequently in C57BL and DBAf mice, lung tumours in A mice, and lymphomata in A and DBAf mice. A small proportion of C57BL, DBAf and IF mice developed tumours of the nervous system. The results are discussed with reference to the ready induction of nervous system tumours in similarly treated rats, and their relevance for human cancer.