The study was conducted on 16 adult male Wistar-Albino rats. The rats in the experimental group (n=8) were exposed to 2.4GHz frequency radiation for over a year. The rats in the sham control group (n=8) were subjected to the same experimental conditions except the Wi-Fi generator was turned off. After the exposure period was complete the possible DNA damage on the rat's brain, liver, kidney, skin, and testicular tissues was detected through the single cell gel electrophoresis assay (comet) method. The amount of DNA damage was measured as percentage tail DNA value.
Numerous peer-reviewed studies have found that cell phone use is not associated with an increased risk of brain tumors. An Oct. 20, 2011 study of 358,403 Danish citizens – the largest study of its kind to date – concluded that "there was no association between tumors of the central nervous system or brain and long term (10 years +) use of mobile phones."  A July 27, 2011 study found that there was no association between cell phone use and brain tumor risks among children and adolescents.  Numerous other studies published from 2001-2013 have similarly concluded that there is no association between cell phone use and the development of brain tumors.      
RF radiation, which includes both radio waves, and microwaves, is at the far end of the electromagnetic spectrum and is a low energy wave. This makes RF and microwave radiation a form of “non-ionizing radiation” which just means that there is enough energy to move the atoms in a molecule around and cause friction, but not enough energy to actually remove a charged particle (ionizing).
Nevertheless, a group of scientists got together in the mid-2000s, calling themselves the BioInitiative Working Group. This group, which largely consisted of wireless radiation researchers, has written a harsh reply as feedback to the reports claiming that posed no health risks. The reply lists a wide range of health effects scientists at the European Commission have unfortunately either ignored or dismissed.