Motorola 120T User Manual page 81

of mobile phones. First, it is uncertain how to apply the results
obtained in rats and mice to humans. Second, many of the
studies that showed increased tumor development used
animals that had already been treated with cancer-causing
chemicals, and other studies exposed the animals to the RF
virtually continuously—up to 22 hours per day.
For the past five years in the United States, the mobile phone
industry has supported research into the safety of mobile
phones. This research has resulted in two findings in
particular that merit additional study:
1 In a hospital-based, case-control study, researchers
looked for an association between mobile phone use and
either glioma (a type of brain cancer) or acoustic neuroma
(a benign tumor of the nerve sheath). No statistically
significant association was found between mobile phone
use and acoustic neuroma. There was also no association
between mobile phone use and gliomas when all types of
types of gliomas were considered together. It should be
noted that the average length of mobile phone exposure in
this study was less than three years.
When 20 types of glioma were considered separately,
however, an association was found between mobile phone
use and one rare type of glioma, neuroepithelliomatous
tumors. It is possible with multiple comparisons of the
same sample that this association occurred by chance.
Moreover, the risk did not increase with how often the
mobile phone was used, or the length of the calls. In fact,
the risk actually decreased with cumulative hours of
mobile phone use. Most cancer causing agents increase
risk with increased exposure. An ongoing study of brain
cancers by the National Cancer Institute is expected to
bear on the accuracy and repeatability of these results.
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 sensitive to
heating, heat alone could have caused the abnormalities
to occur. The data already in the literature on the response
of the micronucleus assay to RF are conflicting. Thus,
follow-up research is necessary.
FDA is currently working with government, industry, and
academic groups to ensure the proper follow-up to these
industry-funded research findings. Collaboration with the
Cellular Telecommunications Industry Association (CTIA) in
particular is expected to lead to FDA providing research
recommendations and scientific oversight of new CTIA-
funded research based on such recommendations.
Two other studies of interest have been reported recently in
the literature:
1 Two groups of 18 people were exposed to simulated
mobile phone signals under laboratory conditions while
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