“We believe that the link between radiofrequency (RF) radiation and tumors in male rats is real,” says John Bucher, the former associate director of the U.S. National Toxicology Program (NTP).
The announcement accompanies this morning’s release of the NTP final reports of studies on cancer in rats and mice exposed to cell phone radiation. Bucher’s project, the largest in NTP history, cost $30 million and took more than ten years to complete.
The NTP found what it calls “clear evidence” that two different types of cell phone signals, GSM and CDMA, increased the incidence of malignant tumors in the hearts of male rats over the course of the two-year study. Higher incidences of brain and adrenal tumors were also seen, but those associations were judged to be somewhat weaker.
“The NTP has now shown what no one believed was possible before the project started,” Ron Melnick told Microwave News. “The assumption has always been that RF radiation could not cause cancer,” he said, “Now we know that was wrong.”
Melnick led the team that designed the animal studies. Melnick retired in early 2009 after close to 30 years as a staff scientist at the NTP.
Schwannomas and Gliomas
On close examination, the NTP results are remarkably consistent with both another recent animal experiment and the existing body of epidemiological studies of cell phone users.
The tumors in the hearts of the rats grew in Schwann cells and are known as schwannomas. Schwann cells make the myelin sheath, which insulates nerve fibers and helps speed the conduction of electrical impulses. They are a key component of the peripheral nervous system and can be found in most organs of the body —of mice, rats and humans.
Schwannomas are very rare and none was seen in the unexposed control rats. Yet, these same malignant tumors of the heart were also found in another large cell phone rat study published earlier this year (see our “More Than a Coincidence”). This latter study was carried out at the Ramazzini Institute in Bologna, Italy.
Tumors of the acoustic nerve, which connects the inner ear to the brain, are called acoustic neuromas. They too grow in Schwann cells and are also known as vestibular schwannomas. Higher rates of acoustic neuroma have been found in epidemiological studies of long-term cell phone users.
The tumors in the brains of the exposed rats grew in glial cells and are known as gliomas. Glial cells are closely related to Schwann cells. As NTP points out in its final report on the rat study:
“The schwannomas observed in the heart and the malignant gliomas observed in the brain arise from a similar functional cell type. Schwann cells are classified as glial cells of the peripheral nervous system.”
Gliomas have also been reported among long-term users of cell phones, including the Interphone study and epidemiological studies in France and Sweden.