Epidemiological studies have suggested that extremely low-frequency magnetic fields (ELF-MF) are associated with an increased incidence of cancer. Studies using in vitro systems have reported mixed results for the effects of ELF-MF alone, and the World Health Organization (WHO) Research Agenda published in 2007 suggested that high priority research should include an evaluation of the co-carcinogenic effects of ELF-MF exposure using in vitro models. Here, the carcinogenic potential of ELF-MF exposure alone and in combination with various stress factors was investigated in NIH3T3 mouse fibroblasts using an in vitro cellular transformation assay. NIH3T3 cells were exposed to a 60Hz ELF-MF (1mT) alone or in combination with ionizing radiation (IR), hydrogen peroxide (H 2O 2), or c-Myc overexpression, and the resulting number of anchorage-independent colonies was counted. A 4h exposure of NIH3T3 cells to ELF-MF alone produced no cell transformation. Moreover, ELF exposure did not influence the transformation activity of IR, H 2O 2, or activated c-Myc in our in vitro assay system, suggesting that 1mT ELF-MF did not affect any additive or synergistic transformation activities in combination with stress factors such as IR, H 2O 2, or activated c-Myc in NIH3T3 cells.
- Cellular transformation
- Combination with stress factors
- Extremely low frequency