(1) To test the hypothesis that sub-chronic whole-body exposure to GSM (global system for mobile communication) 900 microwaves had an effect on tumor promotion and tumor progression and (2) to look for a threshold for the effect in the SAR range from 0.1 to 3.5 W/kg.
Modulation type: pulsed
Exposure duration: repeated daily exposure, 2 h/day, 5 days/week for 9 weeks
|Distance between exposed object and exposure source||1.8 m|
|Chamber||Two identical anechoic chambers (3 m x 3 m x 3 m) were used, one with a base station antenna above the cages and another one for sham exposure.|
|Setup||The animal cages of Plexiglas were divided into 20 separate compartments (6 cm x 6 cm x 17 cm) in two rows that kept the animals parallel to the electric field. Gel phantoms were placed in the 4 outermost compartments in order to provide uniform exposure for the 16 rats.|
|Additional info||In each of the two experiments, the rats were divided into five groups: three groups exposed at different levels, one sham-exposed group, and another untreated cage control group.|
|SAR||3.5 W/kg||spatial average||measured||whole body||-|
|SAR||2.2 W/kg||spatial average||measured||whole body||-|
|SAR||1.4 W/kg||spatial average||measured||whole body||Experiment 1 + 2|
|SAR||0.7 W/kg||spatial average||measured||whole body||-|
|SAR||0.1 W/kg||spatial average||measured||whole body||-|
The findings are negative in terms of latency, multiplicity and tumor volume. With regard to tumor incidence, there was an increase in the rate of incidence at 1.4 W/kg but less at 2.2 W/kg and none at 3.5 W/kg. A trend toward a reduction of malignant tumor incidence and multiplicity was found at the lowest SAR level with a concomitant increase in benign tumor multiplicity.
Overall, these data, which are rather inconsistent, do not bring new evidence of a co-promoting effect of exposure to GSM-900 signals using the DMBA rat model.