Noviembre 2003

Three recent papers from the journal "Radiation Research" reported the effects of radiofrequency radiation (RFR), in cell phone frequencies, on genotoxicity or tumour promotion.

No genotoxic effects after RFR exposure

In this study the authors investigated the induction of genotoxic effects (micronucleus frequency) and the effects on cell cycle kinetics (proliferation index) after exposure of human peripheral blood lymphocytes to 900 MHz electromagnetic fields under different experimental conditions. No statistically significant differences were detected in terms of either micronucleus frequency or cell cycle kinetics.

For more, see "Research - Toxicological experiments - cancer - genotoxicity"

Reference: Zeni O, Chiavoni AS, Sannino A, Antolini A, et al. Lack of genotoxic effects (micronucleus induction) in human lymphocytes exposed in vitro to 900 MHz electromagnetic fields. Radiation Research 2003;160:152-158.

No increase in tumours in rats from long-term exposure to RFR

This study was designed to make a direct measurement of the effect of long-term exposure to RF radiation on the development of cancer in rats. Eighty male and 80 female F344 rats were placed randomly in each of three irradiation groups: the sham group received no irradiation; the FDMA group was exposed to 835.62 MHz FDMA; the CDMA group was exposed to 847.74 MHz CDMA. The animals were exposed from 6 weeks of age. They were irradiated for 4 hours per day, 5 days per week for 2 years. A nominal time-averaged brain SAR value was 1.3 ± 0.5 W/kg.

The authors found that chronic exposure to 835.62 MHz FDMA or 847.74 CDMA RF radiation had no significant effect on the incidence of spontaneous tumours in the rats.

Reference: La Regina M, Moros EG, Pickard WF, Straube WL, et al.
The effect of chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA
radiofrequency radiation on the incidence of spontaneous tumours in rats
Radiation Research 2003;160:143-151.

No consistent effect of RFR on DMBA-induced mammary tumours

This study used dimethyl benz(a)anthracene (DMBA) to promote mammary tumours in Sprague-Dawley rats. DMBA ingestion is a well-established method of promoting cancer in susceptible animals.

In two independent experiments, there was a sham-exposed group and three groups that were exposed to GSM-900 microwaves. In the first experiment the SARs, averaged over the whole body, were 3.5, 2.2, and 1.4 W/kg in the different groups. The SARs in the exposed groups in the second experiment were 1.4, 0.7, and 0.1 W/kg. The DMBA was administered when the rats were 55 days old, and the exposure started 10 days later. The animals were irradiated for 2 hours per day, 5 days per week, for 9 weeks.

Results showed no difference between the groups in terms of latency, number of tumours, or tumour volumes. In the first experiment there was an increase in the rate of tumour incidence at 1.4 W/kg, less at 2.2, and minimal at 3.5. In the second experiment, however, the 1.4 W/kg group showed a decreased rate of incidence. The authors concluded that their results were "globally negative".

Reference: Anane R, Dulou P-E, Taxile M, Geffard M, et al. Effects of GSM-900 microwaves on DMBA-induced mammary gland tumours in female Sprague-Dawley rats. Radiation Research 2003;160:492-497.

For more on these two studies, see "Research - Toxicological experiments - Cancer - tumour growth and development".