Study type: Medical/biological study (experimental study)

Effects of 900 MHz GSM wireless communication signals on DMBA-induced mammary tumors in rats med./bio.

Published in: Radiat Res 2006; 165 (2): 174-180

Aim of study (acc. to author)

To study whether exposure to 900 MHz GSM wireless communication signals enhances mammary tumor development and growth induced by low-dose DMBA.

Background/further details

500 rats were treated with a single dose of 35 mg/kg DMBA and exposure started on the day after DMBA administration.
This study was a parallel project to one part of the PERFORM-A program (International EMF project launched by WHO).



Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 4 h/day, 5 days/week, for 26 weeks
  • SAR: 4 W/kg average over mass (whole body)
  • SAR: 1.33 W/kg average over mass (whole body)
  • SAR: 0.44 W/kg average over mass (whole body)

Exposure 1

Main characteristics
Frequency 900 MHz
  • guided field
Exposure duration repeated daily exposure, 4 h/day, 5 days/week, for 26 weeks
Modulation type pulsed
Additional info

GSM signal

Exposure setup
Exposure source
Chamber The rats where exposed in 12 air-conditioned radial exposure units called wheels, each holding 17 rats. Each week, the exposure positions of each rat on the wheel were rotated one position to the right.
Setup The exposure wheel consisted of a circular cascade of 17 sectored waveguides, all of which were excited by one quarter-loop antenna located in the center and providing uniform circular excitation. The rats were restrained in a horizontal position in metal-free polycarbonate tubes inside the waveguide cavity ventilated from the front where the head of the rat was located.
Sham exposure A sham exposure was conducted.
Additional info Exposure was based on a novel concept using H-polarization to provide reasonable homogeneity of exposure for rats of different sizes.
Measurand Value Type Method Mass Remarks
SAR 4 W/kg average over mass - whole body -
SAR 1.33 W/kg average over mass - whole body -
SAR 0.44 W/kg average over mass - whole body -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
  • breast
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

No significant differences in overall mammary tumor incidence, latency to tumor onset, tumor multiplicity, or tumor size were revealed between exposed and sham exposed groups. Additionally, there were no statistically significant differences in body weight.
There was a tendency for reduction of mammary adenocarcinoma incidence in the lowest exposure group (0.44 W/ kg) compared with the sham exposed rats. Additionally, a higher incidence of adenocarcinoma was noticed in the 4.0 W/kg animals from the 15th to 26th weeks. However, neither tendency was statistically significant; thus this study does not provide evidence that GSM microwave exposure promotes mammary tumor development in rats.
There were significant differences between the cage controls and the experimental groups (sham exposure and exposure). Body weight and mammary tumor incidence in the cage control animals were significantly higher than in the sham exposed and exposed rats. The latency to the mammary tumor onset was significantly shorter in the cage control animals than in the other animals.

Study character:

Study funded by

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