Changing the Conversation on Cell Phone Radio Frequency Radiation Carcinogenesis

Transcription

1 IEEE MW Oct 2016 Changing the Conversation on Cell Phone Radio Frequency Radiation Carcinogenesis James C. Lin University of Illinois at Chicago 851 South Morgan Street (M/C 154) Chicago, Illinois USA Readers of this Magazine may recall my article from a couple of issues back [1] in which I mentioned an unclassified 5-year project, U.S. government-led health effects research study of 2-year (or lifelong in most cases) exposure of rats and mice to radiofrequency (RF) radiation used for wireless cellular telephone operations. This project, which began in 2005, is the largest animal cancer study ever undertaken by the National Toxicology Program (NTP) of the National Institute of Environmental Health Sciences (NIEHS), with a budget of $12 million, at the time. Although years overdue -- project has been ongoing for more than 10 years with huge budget overruns, and an estimated price tag of $25 million or more of U.S. taxpayer s money -- it appears to need still more time to complete data analysis and evaluation. NIEHS/NTP had been rather reluctant to release any reports. In contrast to scientific norm, project personnel have not discussed any results or made any presentations of their findings at scientific meetings. Surprise! Coincidentally, shortly after publication of the Magazine article, on 26 May 2016, the U.S. government project reported occurrences of two types of rare cancers in exposed rats: malignant gliomas in the brain and schwannomas of the heart [2]. These results represented partial findings from the project and purportedly were reviewed by expert peer reviewers selected by NTP and National Institutes of Health (NIH). At an hour-long teleconference held by Linda Birnbaum, the director of the NIEHS and NTP, and John Bucher, the leader of the study and Associate Director of NTP, presented a summary of the report on May 27. Also, Michael Wyde from NTP, who ran the study, made a presentation during a Hot Topics session on Wednesday, June 11, at the BioEM 2016 Meeting of the Bioelectromagnetics Society and European Bioelectromagnetics Association, which took place in Ghent, Belgium.

2 It is interesting to note that the singular and largest animal cancer study ever undertaken by NTP -- cell phone RF exposure of rats and mice project -- was solesourced through a contract to an industrial research firm [3]. Furthermore, reporting occurrences of two types of cancers in RF-exposed rats (malignant gliomas in the brain and schwannomas of the heart) by NTP may have been somewhat of a challenge or perhaps a present dilemma. To wit, John Bucher, the associate director overseeing the NTP study, shared with North Carolina's leading newspapers (the Charlotte Observer and the Raleigh News & Observer in January 2010) that he doubts scientific research can demonstrate a link between cell phones and cancer. Bucher was quoted as saying, "I anticipate either no correlation or, if anything is seen at all, it won t be a strong signal [3]. NIEHS and NTP are physically located in Durham, North Carolina. Equivocal and inconsistent, published animal cancer studies on RF exposures have been controversial [4]. They have posed uncertainty to assessments of health risks from RF exposure. Nevertheless, World Health Organization s International Agency for Research on Cancer (IARC) in 2011 classified exposure to RF electromagnetic fields including those used for cell phones as possibly carcinogenic to humans [5]. IARC had assessed available scientific papers and concluded that while evidence was incomplete and limited, especially with regard to results from animal experiments, published epidemiological studies reporting increased risks for gliomas (a type of malignant brain cancer) and acoustic neuromas (a non-malignant tumor of Schwann-cells sheathed auditory nerves) among heavy or long-term users of cell phones, are sufficiently strong to support a 2B classification of possibly cancer-causing in humans for exposure to RF electromagnetic fields. The NIEHS/NTP s announcement of animal results from their large RF health effect study is a major event. Aside from contributing to current scientific knowledge on a very important public health issue, NTP s richly deserved reputation on identification of chemical and other environmental carcinogens would add more credence to the patchy animal data on exposure to cell phone RF radiation. Given NTP s observation of two types of cancers in RF-exposed rats (malignant gliomas in the brain and Schwannomas of the heart), it is conceivable that IARC could upgrade its epidemiologybased classification of RF exposure to the next higher level of 2A -- probably carcinogenic to humans. That said, it should be noted that the NTP cell phone RF exposure experiment is far from being perfect and it has its flaws and limitations, even though it is large, rather expensive, and took a long time to get to this point. There may even be better ways to do it. But it serves to recognize that few things are known with the degree of certainty that many may take for granted and some would assume or rather prefer.

3 Take the renowned Newton s law of gravity. An apple falling from tree to ground may have inspired Newton to formulate the classic theory of gravitational force. The fact is that apples may not always fall on the same exact spot on the ground each time an apple falls. That spot is influenced by many ambient environmental conditions. Determination of the precise location an apple could fall is replete with uncertainties. The spot on the ground where an apple falls would be subject to wind direction and speed, temperature, humidity, particulate matters in air, and even time of day, among other factors. This happens in physical science where problems have mostly been deemed as deterministic. Exactness is still a matter of probability and statistics. Ponder the case of biology, where variabilities are notorious and vagaries are facts of life. Now back to issue at hand--the NTP study. The announced study included partial findings of occurrences of two rare tumor types in male Harlan Sprague Dawley rats exposed to cell phone RF radiation. What is interesting to note is that while acoustic neuromas in human brains and schwannomas in rat hearts were independently observed from two different mammalian body sites, nevertheless, there could be a connection in that Schwann cells wrap around both nerve tissues in the heart and along the auditory pathways. Gliomas were reported both in human and rat brains from cell phone RF exposure research. The NTP studies involved lifelong (2-year) RF exposures of entire rats and mice bodies using multimode reverberation chambers equipped with shims and mode stirrers to help enhance more uniform RF field distributions inside the chamber. For rats, 900 MHz RF radiation was used as the exposure source. However, beyond the GSM or CDMA modulation and frequency that are primarily used in U.S. wireless networks, no other or specific technical details were provided. Whole-body-average RF absorption rates (SAR) of 0, 1.5, 3, or 6 W/kg; field strengths used for RF exposure were often adjusted to accommodate age related changes in body mass to maintain desired SAR levels. These SARs did not raise body temperature of exposed animals to more than 1ºC. It is noted that 1.6 and 2.0 W/kg are limiting values established by Federal Communications Commission (FCC) in Washington, DC and International Commission on Nonionizing Radiation Protection (ICNIRP) in Munich, Germany, respectively. Exposures to RF were initiated in utero beginning with the exposure of pregnant dams and continuing throughout gestation. After birth, dams and pups were exposed in the same cage through weaning, at which point the dams were removed and exposure of 90 pups per sex per group was continued for up to 106 weeks.

4 A cumulative daily RF exposure duration of about 9 hr/day was conducted 7 days/week over a period of approximately 18 hr for 10 min on and 10 min off cell phone RF radiation. A single, unexposed (0 W/kg) group of each sex served as common, experimental controls for both GSM and CDMA modulations. These control rats were housed in identical reverberation chambers except for RF exposure. The environmental conditions of each chamber was similarly regulated and was maintained on a 12-hr light/dark cycle throughout the studies. The specific findings from the rat studies were occurrences of two rare tumor types in male Harlan Sprague Dawley rats exposed to cell phone RF radiation, malignant gliomas in the brain, and schwannomas of the heart. For malignant gliomas, NTP authors indicated a statistically significant positive SAR-dependent trend in the incidence (p < 0.05) for CDMA-modulated RF radiation. There was not a statistically significant difference between exposed male rats compared to control males for any of the RF groups. While a low incidence (2%) of malignant gliomas was observed in exposed male rats, no malignant gliomas were observed in controls. However, the historical control incidence in NTP studies is also 2.0% (range 0-8%). Moreover, in RF exposed female rats, malignant gliomas were observed in three rats (0.55%); none were found in any of the control females. The historical control incidence at NTP in this case is 0.18% (range 0-2%). Of particular note is schwannomas of the heart. Schwann cells proliferate throughout the body, not only in the heart. They often appear like a sheath wrapped around associated nerve tissues. The number and incidence of schwannomas observed in tissue sites other than the heart of GSM- and CDMA-RF exposed males (11 and 2%) were not significantly different from control rats (3 and 3.3%). NTP s historical control incidence of schwannomas for these rats is 1.3% (range 0-6%). Schwannomas of the heart were observed in male rats in all exposure groups for both GSM- and CDMA-modulated RF radiation (4%), while none were observed in controls. For both modulations, there was a significant SAR-dependent trend in the incidence of schwannomas of the heart (p < 0.05). Moreover, the incidence of schwannomas in the 6 W/kg male rats was significantly higher in CDMA-modulated RFexposed male rats compared to controls. In female Harlan Sprague Dawley rats, there was no statistically significant or RF exposure-related effect on the incidence of schwannomas in the heart or the combined incidence in the heart and other tissue sites.

5 The Schwann cell response to GSM- and CDMA-modulated RF exposure appears to be specific to the heart tissue of male rats. References: [1] J.C. Lin, Human Exposure to Radio Frequency, Microwave and Millimeter Wave Electromagnetic Radiation, IEEE Microwave Magazine, Vol. 17, No. 6, pp 32-36, 2016 [2].M. Wyde, M. Cesta, C. Blystone, S. Elmore, P. Foster, M. Hooth, G. Kissling, D. Malarkey, R. Sills, M. Stout, N. Walker, K. Witt, M. Wolfe, J. Bucher. Report of Partial findings from the National Toxicology Program Carcinogenesis Studies of Cell Phone Radiofrequency Radiation in Hsd: Sprague Dawley rats (Whole Body Exposure), biorxiv, doi: first posted online May 26, 2016 [3] J.C. Lin, The Curious Case of the IARC Working Group on Radio Frequency Electromagnetic Fields and Cell Phones. IEEE Microwave Magazine, Vol. 12, No. 6, pp 32-34, 2011; J.C. Lin, Reply to Letter to the Editor Regarding a Column by Dr. J. C. Lin, IEEE Antennas and Propagation Magazine, Vol. 53, No. 5, pp , 2011 [4]. J.C. Lin, "Carcinogenic Effect of Wireless Communication Radiation in Rodents," Advances in Electromagnetic Fields in Living Systems, Springer, New York, Vol. 5, pp, 35-82, 2009 [5]. R. Baan et al. (on behalf of the WHO International Agency for Research on Cancer Monograph Working Group). Carcinogenicity of Radiofrequency Electromagnetic Fields, The Lancet Oncology, Vol. 12, No. 7, pp , 2011