Cancer-causing effect - not so far

Scientists have found that radio signals from cell phones can activate cell division — a key to the development of tumors — at very low power. The chemical trigger for cell division, extracellular signal-regulated kinases or ERK1/2, was produced by cells as early as five minutes after exposure to the radio signals.

The researchers at the Weizmann Institute of Science in Israel exposed human cells and rat cells to radio signals similar to the 875 megahertz electromagnetic frequency of mobile phones. While the frequency was similar, the power of the signal was only 10 percent of that used in a mobile.

The researchers said that the significance of the findings lies in the fact that cells respond to non-thermal radiation from mobile phones. It was not heat that triggered the production of the ERK1/2 chemical signal for cell division. This could be a separate path to damaging health effects from mobile phones.

Previously, the main scientific assumption underlying conclusions on mobile phone safety is that health hazards come only from heating. Radiation standards, such as those set by the International Commission on Non-Ionizing Radiation Protection, regulate only the heating potential of mobile phones. The guidance assumes that the radiation emission level from mobile phones is too little to heat the brain in a significant way.

Thus, the current standard is that the amount of energy absorbed from a cell phone should not exceed 2 watts per kilogram, averaged over 10 grams of tissue. Virtually all mobile phone models have less than half this amount.

Some scientists remind that cell division is a natural process and that this new study does not prove any health effects. They say the ERK1/2 pathway is also activated by other things such as natural substances produced within the body, chemical stress, and other environmental triggers.

They agree, though, that the research is interesting because it follows the ERK1/2 pathway which is commonly activated in cancer. While the research has achieved a momentary activation of the pathway, more sustained activation is needed for cancer development.

The study so far does not show any cancer-causing effect.

The report on the research study has been published in the Biochemical Journal and the New Scientist. It would bolster the argument of some other researchers who say mobile phones can cause harmful changes in human cells for reasons other than temperature change. The campaign group Powerwatch said that further research must be conducted, but this study shows that guidance standards based only on thermal effects from mobile phones are out of date and should be reviewed.