Note: This study found no significant biological effects under its experimental conditions. We include all studies for scientific completeness.
Lack of promoting effects of chronic exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular system on development of N-ethylnitrosourea-induced central nervous system tumors in F344 rats.
Shirai T, Ichihara T, Wake K, Watanabe SI, Yamanaka Y, Kawabe M, Taki M, Fujiwara O, Wang J, Takahashi S, Tamano S. · 2007
View Original AbstractTwo-year exposure to cell phone radiation at typical SAR levels did not promote brain tumor development in rats.
Plain English Summary
Researchers exposed young rats to cell phone-like radiation (1.95 GHz W-CDMA signals) for 2 years to see if it would promote brain tumor development in animals already given a cancer-causing chemical. The study found no significant increase in brain tumors from the radiation exposure at levels of 0.67 and 2.0 W/kg SAR. This suggests that chronic exposure to this type of cell phone radiation does not accelerate brain tumor formation in this animal model.
Why This Matters
This Japanese study represents one of the more comprehensive animal investigations into cell phone radiation and brain cancer risk, following rats for nearly their entire lifespan. The researchers used a clever approach by first giving rats a known carcinogen (ENU) to initiate tumor development, then testing whether cell phone radiation would promote tumor growth. The SAR levels tested (0.67 and 2.0 W/kg) bracket typical cell phone exposures, which range from about 0.5 to 2.0 W/kg depending on the device and conditions. While the researchers noted non-significant trends toward increased tumors in female rats, the overall results suggest that W-CDMA radiation at these levels does not act as a tumor promoter. However, this study examined only one specific type of cell phone signal and used a tumor promotion model rather than testing whether radiation alone can cause cancer. The broader body of research on EMF and cancer remains mixed, with some large-scale studies like the National Toxicology Program finding increased tumor rates in similar animal models.
Exposure Details
- SAR
- .67 and 2.0 W/kg
- Source/Device
- 1.95-GHz
- Exposure Duration
- 90 min/day, 5 days/week, for 104 weeks
Exposure Context
This study used .67 and 2.0 W/kg for SAR (device absorption):
- 1.7x above the Building Biology guideline of 0.4 W/kg
Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.
Where This Falls on the Concern Scale
Study Details
The present study was performed to evaluate effects of a 2-year exposure to an electromagnetic near-field (EMF) equivalent to that generated by cellular phones on tumor development in the central nervous system (CNS) of rats.
For this purpose, pregnant F344 rats were given a single administration of N-ethylnitrosourea (ENU) ...
The incidence and numbers of brain tumors in female rats exposed to 1.95-GHz W-CDMA signals showed t...
Thus, under the present experimental conditions, exposure of heads of rats to 1.95-GHz W-CDMA signals for IMT-2000 for a 2-year period was not demonstrated to accelerate or otherwise affect ENU-initiated brain tumorigenesis.
Show BibTeX
@article{t_2007_lack_of_promoting_effects_3395,
author = {Shirai T and Ichihara T and Wake K and Watanabe SI and Yamanaka Y and Kawabe M and Taki M and Fujiwara O and Wang J and Takahashi S and Tamano S.},
title = {Lack of promoting effects of chronic exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular system on development of N-ethylnitrosourea-induced central nervous system tumors in F344 rats.},
year = {2007},
url = {https://pubmed.ncbi.nlm.nih.gov/17516507/},
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