The International Collaborative Animal Study of the carcinogenicity and genotoxicity of mobile phone radiofrequency radiation: the Korean study.

A chronic bioassay investigating radiofrequency (RF) carcinogenicity, intentionally designed to be conducted simultaneously in Korea and Japan, using the same research protocol and experimental environment. The study aimed to assess the potential carcinogenicity of Code Division Multiple Access (CDMA)-modulated 900 MHz RF signals at a whole-body specific absorption rate (SAR) of 4 W/kg, which is the reference level of the international human safety guideline, and to verify the key findings from the National Toxicology Program (NTP) study at that SAR level. Two reverberation chamber systems were used for RF exposures, and the same study protocols were followed. Male Harlan Sprague-Dawley (Hsd:Sprague Dawley SD) rats were randomly assigned to cage-control, sham-exposed, or RF-exposed groups. The exposure started on gestational day 5 and lasted for 18 h and 20 min each day, with 10-min on/off cycles. The project included a 28-d toxicity study, a 2-yr carcinogenicity study, and a 14-wk genotoxicity test. Histopathological evaluations were conducted in a partially blinded manner. The results were independently analyzed and submitted separately based on each country's research findings. In the Korean study, no statistically significant changes in tumor incidence or survival rates were observed. No significant RF-related effects were detected in the heart, brain, or adrenal glands. No changes in body temperature. Genotoxicity tests showed no evidence of DNA damage or mutation. In conclusion, the Korean part found that long-term exposure to CDMA-modulated 900 MHz RF was neither carcinogenic nor genotoxic at a SAR of 4 W/kg in male rats. An international animal study was jointly conducted as a chronic bioassay in Japan and Korea to evaluate the carcinogenicity of mobile phone RF signals and to verify key findings from the NTP study using identical protocols and exposure systems.