Electromagnetic fields and carcinogenesis: Interaction of genotoxic and non-genotoxic factors

Full text: Research on cancer-related biological effects of electromagnetic fields (EMF), including both extremely low frequency (ELF) magnetic fields and radiofrequency (RF) fields, is discussed in the light of current understanding of carcinogenesis as a multistep process of accumulating mutations. There is little experimental or theoretical evidence that cancer could be initiated by direct effects of EMF on DNA. Therefore, the presentation focuses on possible 'non-genotoxic' and co-carcinogenic effects. Different animal models and study designs have been used to address possible co-carcinogenic effects. The results of such studies are discussed, as well as other relevant in vivo and in vitro results, and possible mechanisms of EMF effects on carcinogenesis, and the adequacy of the classical two-step initiation/promotion animal experiments for simulating human exposure to the complex mixture of environmental carcinogens. Analogies to known 'non-genotoxic' and co-carcinogenic agents are discussed. It is concluded that very little is currently understood of co-carcinogenesis and 'non-genotoxic' carcinogenesis, and that experiments designed according to the two-step paradigm may not be sufficient for studying the possible role of MF in carcinogenesis. (author)