The National Toxicology Program (part of DHHS) conducted two-year toxicology studies in rats and mice to help clarify potential health hazards, including cancer risk, from exposure to RFR like that used in 2G and 3G cell phones.

The NTP studies found that high exposure to RFR (900 MHz) used by cell phones was associated with:

• Clear evidence of an association with tumors in the hearts of male rats. The tumors were malignant schwannomas.
• Some evidence of an association with tumors in the brains of male rats. The tumors were malignant gliomas.
• Some evidence of an association with tumors in the adrenal glands of male rats. The tumors were benign, malignant, or complex combined pheochromocytoma.

It was unclear if tumors observed in the studies were caused by exposure to RFR in female rats (900 MHz) and male and female mice (1900MHz).

As a follow-up, NTP published an article in October 2019 that evaluated DNA damage in three regions of the brain, the liver, and in blood cells in rats and mice that were removed at an earlier timepoint from the ongoing 2-year toxicology study. DNA damage, if not repaired, can potentially lead to tumors. This work was also included in NTP’s published Technical Reports, but this study includes analyses of the data in the supporting information not included in the Technical Reports.

NTP scientists found that RFR exposure was associated with an increase in DNA damage. Specifically, they found RFR exposure was linked with significant increases in DNA damage in:

• the frontal cortex of the brain in male mice,
• the blood cells of female mice, and
• the hippocampus of male rats.

Learn more here.