In “Can You Hear Me Now?” [Skeptic], Michael Shermer argues correctly that cell phones cannot directly break DNA. But he is wrong to assert that cancer only arises after such damage occurs or that cell phones cannot damage DNA otherwise.
A Tufts University study has found that electrical properties of one type of cell can induce other, distant cells to change their behavior. Twelve different European laboratories working as part of a European Union–sponsored project have found evidence of DNA damage from signals from modern 3G phones. Split samples of human sperm studied in six different national laboratories indicate poorer morphology, motility and increased pathology for cell phone–exposed samples. Other studies in Sweden have found that those who started using cell phones as teenagers have four to five times more brain cancer as adults.
Shermer claims that the latest WHO epidemiological studies suggest no overall increased risk in brain cancer tied with cell phone use. But this project is continuing because its leaders understand the need for continued surveillance.
Department of Epidemiology
University of Pittsburgh
Shermer’s point was that there is not enough energy in microwaves produced by cell phones to cause the breakage of DNA, which can lead to cancer. Although this is true, one cannot conclude that cell phones are not carcinogenic. Research does exist—I am a co-author on a review article relating to it—discussing the carcinogenic effect of elevated tissue temperature with and without coexisting DNA damage from other causes. To my knowledge, no research exists yet on the low-temperature rises that cell phone radiation causes, the increased neurological sensitivity of young individuals, or the unlikely situation where there is known carcinogenic exposure combined with thermal exposure below thermal levels that can cause damage. Consequently, I am hesitant in this case to completely ignore the precautionary principle.
Benjamin L. Viglianti
Department of Radiology
University of Michigan at Ann Arbor
SHERMER REPLIES: [for more on this debate, see www.ScientificAmerican.com/feb2011/skeptic]: Many readers noted that cancer has many causes, such as epigenetic mechanisms that do not require the breaking of DNA chemical bonds, but these other causes are not what most critics are claiming for the alleged connection between cell phone use and brain cancer. Davis agrees with me that “cell phones cannot directly break DNA,” but then she contradicts herself by citing an E.U.-sponsored study on whether DNA damage is linked to 3G phones. The E.U. study has been discredited. The other studies she mentions are either irrelevant or have not been replicated. Viglianti makes a good point that should, in principle, be a testable hypothesis that could lead to a fuller understanding of cancer and its causes. In the meantime, I cannot help but wonder why no one seems concerned about skin cancers caused by holding cell phones in one’s hand and pressed against one’s ear.