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National Cancer Institute is expected to bear on the accuracy and repeatability of these results.1

2.Researchers conducted a large battery of laboratory tests to assess the effects of exposure to mobile phone RF on genetic material. These included tests for several kinds of abnormalities, including mutations, chromosomal aberrations, DNA strand breaks, and structural changes in the genetic material of blood cells called lymphocytes. None of the tests showed any effect of the RF except for the micronucleus assay, which detects structural effects on the genetic material. The cells in this assay showed changes after exposure to simulated cell phone radiation, but only after 24 hours of exposure. It is possible that exposing the test cells to radiation for this long resulted in heating. Since this assay is known to be sensi- tive to heating, heat alone could have caused the abnormalities to occur. The data already in the litera- ture on the response of the micronu- cleus assay to RF are conflicting. Thus follow-up research is neces- sary. 2

FDA is currently working with gov- ernment, industry, and academic groups to ensure the proper follow- up to these industry-funded research findings. Collaboration with the Cellular Telecommunications Internet Association (CTIA) in particular is expected to lead to FDA providing

research recommendations and scientific oversight of new CTIA-funded research based on such recommen- dations.

Two other studies of interest have been reported recently in the litera- ture:

•Two groups of 18 people were exposed to simulated mobile phone signals under lab- oratory conditions while they performed cognitive function tests. There were no changes in the subjects' ability to recall words, numbers, or pictures, or in their spatial memory, but they were able to make choices more quickly in one visual test when they were exposed to simulated mobile phone signals. This was the only change noted among more than 20 vari- ables compared.3

•In a study of 209 brain tumor cases and 425 matched controls, there was no increased risk of brain tumors associated with mobile phone use. When tumors did exist in certain locations, however, they were more likely to be on the side of the head where the mobile phone was used. Because this occurred in only a small num- ber of cases, the increased likelihood was too small to be statistically significant.4

In summary, we do not have enough information at this point to assure the public that there are, or are not, any low incident health problems associated with use of mobile phones. FDA continues to work with all parties, including other federal agencies and industry, to assure that research is undertaken to provide