To study whether exposure to 2.1425 GHz W-CDMA radiofrequency electromagnetic fields induces neoplastic transformation at the exposure limit value of the average whole-body SAR levels based on ICNIRP guidelines.
Mouse embryonic fibroblasts (BALB/3T3 cells) were continuously exposed to radiofrequency electromagnetic fields at specific absorption rates of 80 and 800 mW/kg for 6 weeks. In addition, 3-methylcholanthrene (MCA)-treated cells were exposed in a similar fashion to assess the effects on tumor promotion. Finally, the effect of radiofrequency electromagnetic fields on tumor co-promotion was assessed in cells initiated with MCA and co-exposed to TPA.
|Exposure duration||continuous for 6 weeks|
|Chamber||Two identical RF field exposure incubators, consisting of a horn antenna and a dielectric lens for beam forming and a culture case, were placed in separate anechoic chambers, and a mechanical switch in a dummy box was used to select RF or sham exposure.|
|Setup||This system allowed simultaneous exposure of 49 (7 x 7 array) 35-mm culture dishes with a similar SAR uniformity within each dish [Iyama et al., 2004].|
|Sham exposure||A sham exposure was conducted.|
|Additional info||Identical air at 37 °C, 5% CO2, and >90% humidity was provided to the two culture units through sealed ducts.|
No significant differences in transformation frequency were found between the test groups exposed to radiofrequency electromagnetic fields and the sham exposed controls in the non-, MCA-, or "MCA plus TPA"-treated cells.
The data provided no evidence to support the hypothesis that radiofrequency electromagnetic fields may affect malignant transformation. Thus, the results suggest that exposure to low-level radiofrequency irradiation of up to 800 mW/kg does not induce cell transformation, which causes tumor formation.