Given the high level of anxiety and controversy that surrounds the question of whether cell phones can cause cancerous brain tumors, it's surprising that this new study, from scientists at the Weizmann Institute of Science in Israel, hasn't gotten more attention in this country. Though not quite accurate, this headline from London's Daily Mail gives you the gist: "Only ten minutes on a mobile could trigger cancer."Actually, what the pair of Israeli scientists, Joseph Friedman and Rony Seger, found was that radiation emitted from cell phones can trigger cellular changes that could interfere with the process of cell division, which in turn could lead to the growth of tumors. Here's the billboard sentence from the study, published in the Biochemical Journal:

"Thus this study demonstrates for the first time a detailed molecular mechanism by which electromagnetic irradiation from mobile phones induces the activation of the ERK cascade and thereby induces transcription and other cellular processes."

ERK stands for "extracellular-signal-regulated kinase," a cellular enzyme that forms "cascades" or pathways that can regulate the effects of external stimuli on processes including cell replication and "apoptosis," the normal process of programmed cell death that the body uses to dispose of cellular debris.

This finding is important because, while long-term cell-phone use has been linked to higher risk of developing brain tumors, there's never been evidence of a specific physiological link or pathway by which they might actually cause changes in brain chemistry. "The [cell-phone] frequencies are too low to damage DNA directly," writes Caroline Williams in New Scientist, "and the power of the signal is well below the level that could overheat cells."

Last year a Swedish study examining cancer rates in people with "extensive" mobile usage (over 2,000 hours of cell phone time, spread over many years) found that their risk of developing brain tumors was as much as 240% higher than a person who has never used one.

Now the Weizmann research has established that pathway: Friedman and Seger exposed human and rat cells to radiation at 875 megahertz, slightly lower than cell-phone frequencies. Within minutes, the ERK cascades were activated.

"The significance lies in showing cells do react to cell phone radiation in a nonthermal way," Seger told New Scientist.

But the scientists were careful to point out that there is still no evidence to suggest a direct link between radiation from mobile phones and cancer -- meaning that the "cell phones cause cancer" headlines are misleading. Their work only proves that certain cells can react to cell-phone radiation.

That alone should be enough to trigger further investigation -- and to convince more heavy mobile talkers to use hands-free headsets.