Study on potential effects of "902-MHz GSM-type Wireless Communication Signals" on DMBA-induced mammary tumours in Sprague-Dawley rats.
The aim of the study was to detect whether long-term exposure to "902-MHz GSM-type Wireless Communication Signals" ("radio-frequency (RF)-exposure") would affect 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumours in female Sprague-Dawley rats. Five hundred female rats were each given a single oral dose of 17 mg DMBA per kg body weight (bw) at an age of 46-48 days. Three groups of 100 animals each were RF-exposed (902 MHz; crest factor 8; pulse width=0.57 ms) from the next day onwards to normal whole-body averaged doses (expressed as specific absorption rate, SAR) of 0.4, 1.3 or 4.0 W/kg bw (low/mid/high-dose group) for 4h/d, 5d/week, during 6 months. A sham-exposed and a cage-control group remained without RF-exposure (<<0.01 mW/kg). Animals were weekly weighed and palpated for mammary tumours; all mammary glands were examined histopathologically. There were several statistically significant differences between RF-exposed groups and the sham-exposed group, as follows: All RF-exposed groups had, at different times, significantly more palpable tissue masses. There were fewer animals with benign neoplasms, but more with malignant tumours in the high-dose group. In addition, there were more adenocarcinomas in the low-dose group, more malignant neoplasms in the low- and high-dose groups, more animals with adenocarcinomas in the high-dose group, and fewer animals with fibroadenomas in the low- and mid-dose groups. The cage-control group had, when compared with the sham-exposed group, statistically significantly more palpable tissue masses, more benign and also more malignant neoplasms. The cage-control group had in most aspects the highest incidence and malignancy of neoplasms among all groups. None of the above findings in RF-exposed animals produced a clear dose-response relation and the responses of the cage-control group were either similar to or stronger than those of any of the RF-exposed group. The significant differences between the sham-exposed animals and one or more RF-exposed groups may be interpreted as evidence of an effect of RF-exposure. In the context of the results of the cage-control group, in the light of controversial results reported in the literature, and given the fact that the DMBA-mammary tumour model is known to be prone to high variations in the results, it is the authors' opinion that the differences between the groups are rather incidental ones.
Hruby
Robert
R
Austrian Research Centers GmbH-ARC, Seibersdorf, Austria. robert.hruby@arcs.ac.at
Neubauer
Georg
G
Kuster
Niels
N
Frauscher
Michael
M
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity*; D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000528:radiation effects; D005260:Female; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects*; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000209:etiology* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects / Q000528:radiation effects; D011846:Radio Waves / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D047368:Tumor Burden / Q000187:drug effects / Q000528:radiation effects
D015127:9,10-Dimethyl-1,2-benzanthracene