Low-frequency electromagnetic radiation enhances the induction of rat mammary tumors by nitrosomethyl urea.

Low-frequency electromagnetic fields enhance the induction of mammary gland tumors in rats using nitrosomethyl urea. The incidence of tumors depended on the duration of exposure to static (dc) and variable (ac) magnetic fields. Variable magnetic fields induced mammary gland cancer much more frequently than static ones. Apart from increasing the incidence of mammary gland tumors, household low-frequency electromagnetic fields reduced the mean latent period of tumor development and led to predominance of malignant tumors in the exposed animals as compared to controls. Mammary gland tumors developed rarely under the effect of static or variable magnetic fields per se, without preliminary administration of a carcinogen. Household low-frequency electromagnetic fields may potentially present an oncogenic hazard for animals and humans.