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Cancer & Tumors

The 1.5 GHz electromagnetic near-field used for cellular phones does not promote rat liver carcinogenesis in a medium-term liver bioassay.

No Effects Found

Imaida, K, Taki, M, Watanabe, S, Kamimura, Y, Ito, T, Yamaguchi, T, Ito, N, Shirai, T, · 1998

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Cell phone radiation at 1.439 GHz showed no cancer-promoting effects in rat livers despite causing measurable biological stress responses.

Plain English Summary

Summary written for general audiences

Researchers exposed rats to 1.439 GHz radiofrequency radiation (the type used in Japanese cell phones) to see if it would promote liver cancer development. Despite using exposure levels up to 1.91 W/kg and finding evidence of biological stress (increased stress hormones), the radiation did not increase cancer-promoting changes in the liver. This suggests that cell phone radiation at these levels does not accelerate liver cancer progression in this animal model.

Why This Matters

This 1998 Japanese study provides important context for understanding EMF cancer research, particularly because it tested frequencies and exposure protocols specific to cellular technology actually used in Japan at the time. The researchers found biological evidence that the rats were responding to the EMF exposure (elevated stress hormones including corticosterone and ACTH), yet this didn't translate into cancer promotion in the liver. What's notable is the exposure levels tested - peak SARs up to 1.91 W/kg exceed current safety limits for localized exposure. However, we must interpret these findings carefully within the broader cancer research landscape. This study examined cancer promotion (whether EMF accelerates existing cancer processes) rather than cancer initiation, and focused specifically on liver effects. The reality is that cancer research requires looking at the totality of evidence across multiple studies, exposure types, and biological endpoints before drawing conclusions about human health risks.

Exposure Details

SAR
0.680-0.453 and 1.91 - 0.937 W/kg
Source/Device
1.439 GHz
Exposure Duration
90 min a day, 5 days a week, over 6 weeks

Exposure Context

This study used 0.680-0.453 and 1.91 - 0.937 W/kg for SAR (device absorption):

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 Exposure Level in ContextStudy Exposure Level in ContextThis study: 0.680-0.453 and 1.91 - 0.937 W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects observed in the Extreme Concern range (Building Biology)FCC limit is 4 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 1.44 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 1.44 GHzPower lines50/60 Hz5G mm28 GHzLogarithmic scale

Study Details

In the present study, a 1.439 GHz electromagnetic near-field (EMF), another microwave band employed for cellular phones in Japan, was similarly investigated.

Time division multiple access (TDMA) signals for the Personal Digital Cellular (PDC) Japanese cellul...

Despite increased serum levels of corticosterone, adrenocorticotropic hormone (ACTH) and melatonin, ...

These findings clearly indicated that local body exposure to a 1.439 GHz EMF, as in the case of a 929.2 MHz field, has no promoting effect on rat liver carcinogenesis in the present model.

Cite This Study
Imaida, K, Taki, M, Watanabe, S, Kamimura, Y, Ito, T, Yamaguchi, T, Ito, N, Shirai, T, (1998). The 1.5 GHz electromagnetic near-field used for cellular phones does not promote rat liver carcinogenesis in a medium-term liver bioassay. Jpn J Cancer Res 89(10):995-1002, 1998.
Show BibTeX
@article{imaida_1998_the_15_ghz_electromagnetic_3099,
  author = {Imaida and K and Taki and M and Watanabe and S and Kamimura and Y and Ito and T and Yamaguchi and T and Ito and N and Shirai and T and},
  title = {The 1.5 GHz electromagnetic near-field used for cellular phones does not promote rat liver carcinogenesis in a medium-term liver bioassay.},
  year = {1998},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/9849576/},
}
PubMed: 9849576

Cited By (60 papers)

View all 60 citing papers on Semantic Scholar

Quick Questions About This Study

A 1998 study found that cell phone radiation at 1.439 GHz did not promote liver cancer development in rats, even at high exposure levels. Despite causing measurable biological stress, the radiation showed no cancer-promoting effects on liver tissue in this research model.
Research shows cell phone radiation can cause biological stress responses in the liver, including increased stress hormones like corticosterone. However, a key study found this radiation did not promote actual cancer development or harmful cellular changes in liver tissue.
A controlled study exposed rats to 1.4 GHz radiation and found no liver cancer promotion despite using high exposure levels. While the radiation triggered stress hormone responses, it did not cause harmful changes to liver cells or accelerate cancer progression.
Current research suggests minimal liver cancer risk from phone radiation. A 1998 study using Japanese cell phone frequencies found no cancer-promoting effects in rat liver tissue, even though the radiation caused detectable biological stress responses in the animals.
Cell phone EMF can trigger stress responses in liver tissue, increasing hormones like corticosterone and ACTH. However, research indicates these biological changes don't translate to cancer promotion or significant harmful effects on liver cell structure and function.