Oncogenic properties of transplacentally acting ethyl-nitrosourea in NMRI-mice after antecedent X-irradiation.

The successive application of X-irradiation and ethylnitrosourea during the fetal period in NMRI-mice results in tumorous as well as in degenerative diseases in offspring. Leukemia and ovarial tumor incidences are increased when compared with animals either treated alone, whilst lung and liver tumors appear at a lower rate. Liver necroses and kidney cysts are further outstanding pathological findings after combined treatment. These results can be parallelled with the known postirradiational proliferative capacities of the affected fetal tissues, and possibly are a sensitive indicator for such radiation induced alterations.