A study by the Department of Health and Human Services's National Toxicology Program discovered a link between cellphone radiation and two types of cancer. Reporting on its partial results so far, researchers found low incidences of heart and brain tumors in male rats. (Reuters)

First things first: No one has proven that cellphones cause cancer. No one has proven that cellphones cause cancer. In fact, most research suggests otherwise! But you might not realize that, based on some news circulating Friday morning. Many publications, including the Wall Street Journal and Mother Jones, are trumpeting the results of a U.S. government study that links cellphones to tumor growth.

But while the WSJ ran with the scary "Cellphone-Cancer Link Found in Government Study," something like "Research That Hasn't Been Vetted Yet Shows Possible Link Between Cellphones and Cancer in Male Rats" might have been more appropriate.

Less sexy! But also a lot less misleading.

The study, released on Thursday after the results leaked online, is the result of a $25 million, multi-year effort from the National Toxicology Program (NTP). But it hasn't been peer reviewed — despite implications to the contrary by the WSJ — because it hasn't been formally submitted to a scientific journal and accepted for publication, during which time outside experts would have had the opportunity to pinpoint possible errors or exaggerations in the data and analysis. Several experts reportedly reviewed the work before it was announced, but the researchers have not yet made all of their data public.

Ron Melnick, who was the lead investigator on the study until he retired in 2009, told STAT News that he was asked to review the data and found that they “indicated that there were increased tumor responses in the brain and the heart."

“Where people were saying there’s no risk, I think this ends that kind of statement,” he told the WSJ.

The researchers exposed mice and rats to radio-frequencies commonly used by wireless electronics, at doses comparable to a human's typical exposure. Of the male rats dosed with radiation, the study authors report, 2 to 3 percent contracted gliomas, or tumors of the glial cells of the brain, and 6 to 7 percent percent developed schwannoma tumors in their hearts. None of the non-dosed rats developed any tumors. But STAT points out that it's unusual that none of these non-dosed rats randomly developed tumors on their own, and that the cancer rates in the dosed rats might actually be pretty similar to what you'd usually expect in a random rat population.

There was no significant cancer uptick in the female rats dosed with radiation, and the researchers have not released their data on male or female mice.

All of this is to say that it's way too soon to take these findings as a reason to toss your phone out the window. We've explained before that single studies are basically useless on their own (here's why) and that's still the case. This research will almost certainly inspire new projects that try to replicate the troubling results, and that's great. But when publications blast every contrarian new finding as a groundbreaking absolute truth, it makes the public less able to develop informed opinions.

"There are arguments in the literature now that we are at the beginning of an epidemic of cancers," Chris Portier, former associate director of the NTP, told Mother Jones. "There are arguments against that. It is not clear who is right. I have looked through it. It's a mixed bag."

Indeed, most studies examining the human population over time have concluded no association between cellphone use and increased rates of cancer. Some have argued that we just haven't been using cellphones long enough to see the ill-effects borne out, but the University of Sidney's Simon Chapman recently argued against this line of thinking.

"That is not what we see with cancer," he wrote in an op-ed for Quartz. "We see gradual rises moving toward peak incidence, which can be as late as 30 to 40 years (as with lung cancer and smoking)." And his research — and that produced by other scientists — has failed to show the start of such a trend.

Maybe this study really is a major turning point in understanding of the risk of cell phone usage. But it's way too soon to tell.

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