Study type: Medical/biological study (experimental study)

Microwaves from Mobile Phones Inhibit 53BP1 Focus Formation in Human Stem Cells Stronger than in Differentiated Cells: Possible Mechanistic Link to Cancer Risk. med./bio.

Published in: Environ Health Perspect 2010; 118 (3): 394-399

Aim of study (acc. to author)

To study whether microwaves from GSM or UMTS mobile telephones induce double-strand breaks or affect double-strand break DNA repair in stem cells or fibroblasts.

Background/further details

Heat treatment (41°C) was used as positive control for stress response. Gamma radiation (3 Gy) was used as positive control for genotoxic effects.
The measurement parameter of 53BP1 foci inhibition was used to study double-strand breaks. The authors suggest that inhibition of 53BP1 foci formation might be caused by a decrease in accessibility of double-strand breaks to proteins because of stress-induced chromatin condensation or by inhibition of phosphorylation of the 53BP1 protein that is necessary to activate the protein for DNA repair.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Exposure duration: continuous for 1 h, 2 h or 3 h
GSM 1
Exposure 2: 905 MHz
Exposure duration: continuous for 1 h, 2 h or 3 h
GSM 2
Exposure 3: 1,947.4 MHz
Exposure duration: continuous for 1 h, 2 h or 3 h
Exposure 4: 915 MHz
Exposure duration: continuous for 1 h/day, 5 days/week, for 2 weeks
GSM 1
Exposure 5: 905 MHz
Exposure duration: continuous for 1 h/day, 5 days/week, for 2 weeks
GSM 2
Exposure 6: 1,947.4 MHz
Exposure duration: continuous for 1 h/day, 5 days/week, for 2 weeks

Exposure 1

Main characteristics
Frequency 915 MHz
Type
Exposure duration continuous for 1 h, 2 h or 3 h
Additional info GSM 1
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 37 mW/kg - - - -

Exposure 2

Main characteristics
Frequency 905 MHz
Type
Exposure duration continuous for 1 h, 2 h or 3 h
Additional info GSM 2
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 37 mW/kg - - - -

Exposure 3

Main characteristics
Frequency 1,947.4 MHz
Type
Exposure duration continuous for 1 h, 2 h or 3 h
Additional info UMTS
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 39 mW/kg - - - -

Exposure 4

Main characteristics
Frequency 915 MHz
Type
Exposure duration continuous for 1 h/day, 5 days/week, for 2 weeks
Additional info GSM 1
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 37 mW/kg - - - -

Exposure 5

Main characteristics
Frequency 905 MHz
Type
Exposure duration continuous for 1 h/day, 5 days/week, for 2 weeks
Additional info GSM 2
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 37 mW/kg - - - -

Exposure 6

Main characteristics
Frequency 1,947.4 MHz
Type
Exposure duration continuous for 1 h/day, 5 days/week, for 2 weeks
Additional info UMTS
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 m
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 0.25 W - - - -
SAR 39 mW/kg - - - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The data showed that microwave exposure inhibited the formation of 53BP1 foci in human primary fibroblasts and mesenchymal stem cells. The GSM carrier frequency (915 MHz) and UMTS frequency band (1947.4 MHz) were effective for both cell types. Exposure at 905 MHz did not inhibit 53BP1 foci formation in differentiated cells, either fibroblasts or lymphocytes (as found in a previous study, see Belyaev et al. 2009), whereas some effects were seen in stem cells at 905 MHz (statistically not significant trend to foci inhibition). Contrary to fibroblasts, stem cells did not adapt to chronic exposure during two weeks (i.e. foci inhibition was still present).
In conclusion, the data indicate that stem cells are more sensitive to microwave exposure than differentiated human primary fibroblasts (or lymphocytes as shown in the previous study). The fact that stem cells are more sensitive to microwave exposure and react to more frequencies than do differentiated cells may be important for cancer risk assessment and indicate that stem cells are the most relevant cellular model for validating safe mobile communication signals.

Study character:

Study funded by

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