2026 Short Takes
Letters to the Editor Are in the Works
Korean researchers working on NTP Lite have joined their Japanese collaborators in reporting no evidence of adverse effects among rats chronically exposed to cell phone radiation.
“Long-term exposure to CDMA-modulated 900 MHz RF was neither carcinogenic or genotoxic at an SAR of 4 W/Kg in male rats,” Young Hwan Ahn and coworkers write in Toxicological Sciences, the same journal that published the Japanese results a few days ago. The Korean paper was posted on January 16.
NTP Lite is a scaled down version of the U.S. NTP RF–cancer animal study. For background, go here.
The Japanese and Korean papers have prompted a raft of criticism. A number of letters to the editor of the journal are being prepared, Microwave News has been told.
“It’s very obvious that the objective of the paper is to neutralize the results of the NTP study,” Henry Lai, professor emeritus at the University of Washington, Seattle, said of the Japanese study. “The authors have lost their objectivity as scientists —and, sadly, they don’t seem to know much about RF science.”
The NTP Lite project, which got underway in 2019, is running far behind schedule. RF exposures were completed in 2022, followed by years of analysis.
One reason for the delay of the Korean experiment was the premature death of at least four of the RF-exposed rats. This led to the genotoxic component of the study being carried out separately. (See our report from June 2023.) The death of those rats remains unexplained.
The project was designed for the data from the two countries to be combined —to enhance statistical reliability. But, neither of the published papers addresses where that stands.
The full text of the Korean paper (abstract below) is open access, as is the Japanese paper.
Korean Findings Are Still Pending
The Japanese team working on a partial repeat of the NTP RF–animal cancer study has reported seeing no “reproducible” effects on cancer or genotoxicity in RF-exposed male rats.
The project —nicknamed NTP Lite— is a scaled-down version of the $30+ million project carried out by the U.S. National Toxicology Program which found “clear evidence” that RF radiation can cause cancer in rats. The NTP final report was released in 2018.
The Japanese results were published in the journal Toxicological Sciences yesterday, January 12. The paper is open access.
“This study performed in Japan, jointly planned and executed by Japan and Korea, provides strong evidence that long-term exposure to 900 MHz RF-EMFs did not produce reproducible carcinogenic or genotoxic effects in male rats,” states Katsumi Imaida of Japan’s Kagawa University, the leader of the Japanese study group.
“No statistically significant increases in the incidences of neoplastic or non-neoplastic lesions were found in any major organ, including the brain, heart, and adrenal glands. Genotoxicity assays revealed no evidence of DNA damage or chromosomal aberrations in RF-exposed rats,” according to the Japanese abstract.
The results of the parallel Korean experiment have not yet been released. The original plan was to combine the Japanese and Korean data to achieve greater statistical reliability. The leader of the Korean arm of the project is Young Hwan Ahn of Ajou University School of Medicine.
NTP Lite is years behind schedule. Work on the project began in 2018 and the RF exposures were scheduled to be completed over three years ago. Since then some partial reports have dribbled out (more here, here and here), leading some observers to suggest that the project would be unable to resolve the RF–cancer question.
For example, Microwave News was told last year that a group of animals were to be exposed to RF at 6 W/Kg in the Japanese experiment, but that part of the protocol was quietly abandoned. The new paper does not mention the 6 W/Kg animals, which were designed to serve as positive controls.
Joel Moskowitz of the UC Berkeley School of Public Health, who runs the Electromagnetic Radiation Safety website, offered the following comment based on a preliminary reading of the new Japanese study: “A null result in the Japanese NTP Lite study should not be considered a refutation, because it is underpowered to see relatively low‑incidence tumors.”
Here is the abstract of the published paper:
This is a developing story and will be updated as further details emerge.
Korean Paper Published
January 18, 2026
The Korean team of NTP Lite has published its own paper, with results similar to those seen in Japan —no adverse effects. For he latest on both papers, go here.