Undifferentiated sarcomas induced in Syrian hamsters by subcutaneous injection of diethylstilbestrol

The carcinogenic effects of weekly subcutaneous injections of dimethylnitrosamine (NDMA: 0.05 of the LD50) and diethylstilbestrol (DES: 1.5 mg/kg body wt) or a combination of both carcinogens were studied in 64 Syrian hamsters. There was no additional tumorigenic effect on NDMA-induced liver tumours in hamsters which received DES treatment prior to NDMA treatment. In contrast to the previously reported DES effects, 72% of the DES-treated hamsters unexpectedly developed undifferentiated sarcomas around the interscapular injection site. This finding suggests a local carcinogenicity of DES, which might not be related to its hormonal effects.