Friday, August 04, 2006
A study shows that the effects of cell-phone radiation may depend on your genes.

By Duncan Graham-Rowe

The way a living cell responds to radio waves from a cell-phone could depend on the cell's genetic makeup, according to a new study carried out in Finland. And these findings may suggest how the effects of cellular radiation vary from person to person.

The study, which is the first to examine how the impact of cell phone exposure might be affected by genomic differences, could also help to explain why attempts to replicate previous studies linking cell-phone use with health problems have failed, says Dariusz Leszczynski, head of radiation biology at the Radiation and Nuclear Safety Authority in Helsinki, who led the research.

But Leszczynski emphasizes that the study itself "cannot be in any way used for speculation for possible health effects...This shows only that different cells can respond differently."

The possibility that cell-phone radiation causes adverse health effects has been a controversial topic for nearly two decades. Consumers and scientists have claimed that exposure to these radio waves can cause different types of cancer, as well as other diseases.

Yet most scientists remain sceptical. For one thing, it's hard to explain using conventional physics how the low-energy levels of this non-ionizing radiation could cause the chemical breaks in DNA strands and other genotoxic effects that cause tumors.

In the new study, due to be published in the journal Proteomics, Leszczynski and collaborators used two sets of cultured human endothelial cells that were slightly different genetically. Both were exposed to 900 MHz GSM cell-phone radiation, then tested to see which genes had been expressed, by examining the RNA present -- a technique known as transcriptomics. In a second set of tests, the cells were screened to see if there were any changes in the amount of proteins expressed -- a process known as proteomics.

In both sets of cells, the radiation appeared to produce an effect, causing changes in the gene and protein expression, compared with control cells that were not exposed. However, the types of gene and protein affected in the two sets of exposed cells varied greatly, indicating that their slight genetic differences were influencing the cells' responses to the radiation. Both techniques were repeated multiple times.

"This is an interesting piece of work and is likely to contribute to a better understanding of the effects [of cell-phone radiation]," says Michael Clark, a spokesperson for the Health Protection Agency, an independent organization that advises the British government on issues of health. But he warns that it does not tell us anything about the safety of cell phones. "Biological effects have been observed before and they do not necessarily correspond to health effects," he says.

Franz Adlkofer, a scientist at the Verum Foundation in Munich, Germany, who led an international study that did find evidence of DNA damage induced by cell-phone radiation, says genetic variability is a likely contributor. "I'm absolutely sure that not all people have the same susceptibility [to the effects of cell phones]," he says.

Others are less convinced that the cell studies will be applicable to humans. "Studies carried out at the cellular level are normally used to investigate mechanisms of interaction, but are not generally taken alone as evidence of effects in vivo," says Chiyoji Ohkubo, a physiologist with the World Health Organization's International Electromagnetic Fields (EMF) project.

Last year, the WHO co-sponsored a review of proteomics and transcriptomics techniques to study cell-phone safety, he says. "The ultimate consensus of the assembly was that a research approach that employs [these techniques] is useful for scientific investigation of [electromagnetic field] effects, but that it is not yet ready, and should not be used, for health risk assessment," says Ohkubo.

Leszczynski accepts this, and adds that large, long-term studies are probably the only way to uncover the health effects of cell phones.

A few such studies are already in the works. If they do show health effects, Leszczynski says, it will be important to have an understanding of the biological mechanisms behind them -- and this is where proteomics and transcriptomics can help. "We need to get information about what is happening inside the cells," he says.