Researchers say there might be a link between cellphone radiation and cancer — a potentially huge finding considering how widespread cellphones are today. On Thursday, the U.S. National Toxicology Program released partial results from a two-year study on cellphones and rats. Researchers say the rats in the study developed brain and heart tumors that were "likely the result of whole-body exposures" to radiofrequency radiation, which is the type that cellphones emit. It's important to note the rats got the same amount of radiation that humans get when using cellphones. Chris Portier, former associate director of the toxicology program and commissioner of this study, told Mother Jones: "I think this is a game changer. ... The NTP does the best animal bioassays in the world. Their reputation is stellar. So if they are telling us this was positive in this study, that's a concern. " The debate over whether cellphones cause cancer is a longstanding one, but this might be one of the most extensive, high-profile studies we've seen in a long time. The National Cancer Institute says while cellphones produce non-ionizing radiation, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk. "According to Pew Research Center, 92 percent of American adults say they own a cellphone. Of that group, 90 percent say they "frequently" carry those phones with them. The full results from the NTP study have yet to be released but are expected to be made public by the end of 2017. This video includes images from Getty Images and Tony Alter / CC BY 2.0.