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Larry E. Anderson,¹ James E. Morris,¹ Lyle B. Sasser,¹ and Wolfgang Löscher²

¹Environmental and Health Sciences Division, Battelle, Richland, Washington, USA
²Department of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, Hannover, Germany

Abstract

In line with the possible relationship between electric power and breast cancer risk and the underlying melatonin hypothesis, 50-Hz magnetic field (MF) exposure at microtesla flux densities for either 13 or 27 weeks significantly increased the development and growth of mammary tumors in a series of experiments from Löscher's group in Germany. Löscher's group used the 7,12-dimethylbenz[a]anthracene (DMBA) model of breast cancer in Sprague-Dawley rats. The finding could not be replicated when a similar experimental protocol was used in a study conducted by Battelle in the United States. In the present paper, investigators from the two groups discuss differences between their studies that might explain the apparent discrepancies between the results. These differences include the use of different substrains of Sprague-Dawley rats (the U.S. rats were more susceptible to DMBA than the European rats) , different sources for diet and DMBA, differences in environmental conditions, and differences in MF exposure metrics. Furthermore, the effects of MF exposure reported by Löscher's group, albeit significant, were weak. We also discuss the general problem of replicating such weak effects. Key words: breast cancer, electric power, electromagnetic fields, melatonin. Environ Health Perspect 108:797-802 (2000) . [Online 21 July 2000]

http://ehpnet1.niehs.nih.gov/docs/2000/108p797-802anderson/ abstract.html

Address correspondence to W. Löscher, Department of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, Bünteweg 17, D-30559 Hannover, Germany. Telephone: 49 511 953 8720. Fax: 49 511 953 8581. E-mail: wloscher@pharma.tiho-hannover.de

We thank C. Polk for discussion on differences in environmental parameters that could conceivably have been responsible for different outcomes of the experimental studies. We also thank M. Mevissen, a former investigator in the Hannover group, for discussion during preparation of the manuscript.

The experiments of the Battelle study were supported by the National Institute of Environmental Health Sciences through the U.S. National Toxicology Program. The experiments of Löscher's group were supported by equipment from the Forschungsverbund Elektromagnetische Verträglichkeit Biologischer Systeme (Department of High Voltage Engineering, Technical University, Braunschweig, Germany) and by a grant from the U.S. Department of Energy, Office of Utility Technologies, through Oak Ridge National Laboratory under subcontract 19X-SU446V.

Received 14 February 2000 ; accepted 10 May 2000.