Medical/biological study (experimental study)

Exposure of Sprague-Dawley rats to a 50-Hertz, 100-microTesla magnetic field for 27 weeks facilitates mammary tumorigenesis in the 7,12-dimethylbenz[a]-anthracene model of breast cancer med./bio.

By: Thun-Battersby S, Mevissen M, Loscher W

Published in: Cancer Res 1999; 59 (15): 3627-3633

Aim of study (acc. to author)

To investigate the effects of a 27 week magnetic field exposure on DMBA induced tumor development in rats.

Background/further details

After one week of magnetic field or sham exposure 10 mg/rat DMBA was administered and exposure or sham exposure was continued for 26 weeks.

Endpoint

cancer: mammary tumors

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Modulation type: CW Exposure duration: 24 h/day, 7 days/week, for 27 weeks	magnetic flux density: 100 µT effective value electric field strength: 60 V/m maximum (20-60 V/m)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Polarization	linear
Exposure duration	24 h/day, 7 days/week, for 27 weeks
Additional info	horizontal

Modulation

Modulation type	CW

Exposure setup

Exposure source	coil(s)
Chamber	exposure chambersa, 9 rats/cage
Setup	Mf horizontal and parallel to horizontal component of the earth's MF

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	effective value	-	-	-
electric field strength	60 V/m	maximum	cf. remarks	-	20-60 V/m

Additional parameter details

sham exposure < 0,1µT static earth MF 40 µT

Exposed system:

Methods Endpoint/measurement parameters/methodology

cancer: palpation in vivo and histological examination post mortem of tumors

Investigated system:

investigation on living organism

Investigated organ system:

breast

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

Magnetic field exposure enhanced tumor development and growth significantly, detected by palpation. The incidence of histologically verified mammary tumors was statistically significant higher in exposed rats compared with sham-exposed animals.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Department of Energy, USA

Comments on this article

Anderson LE et al. (2000): Effects of 50- or 60-Hertz, 100 µT magnetic field exposure in the DMBA mammary cancer model in Sprague-Dawley rats: possible explanations for different results from two laboratories

Soffritti M et al. (2016): Life-span exposure to sinusoidal-50 Hz magnetic field and acute low-dose gamma radiation induce carcinogenic effects in Sprague-Dawley rats
Fedrowitz M et al. (2012): Gene expression in the mammary gland tissue of female Fischer 344 and Lewis rats after magnetic field exposure (50 Hz, 100 muT) for 2 weeks
Fedrowitz M et al. (2012): Effects of 50 Hz magnetic field exposure on the stress marker alpha-amylase in the rat mammary gland
Soffritti M et al. (2010): Mega-experiments on the carcinogenicity of Extremely Low Frequency Magnetic Fields (ELFMF) on Sprague-Dawley rats exposed from fetal life until spontaneous death: plan of the project and early results on mammary carcinogenesis
Girgert R et al. (2009): Exposure of mcf-7 breast cancer cells to electromagnetic fields up-regulates the plasminogen activator system
Negishi T et al. (2008): Lack of promotion effects of 50 Hz magnetic fields on 7,12-dimethylbenz(a)anthracene-induced malignant lymphoma/lymphatic leukemia in mice
Fedrowitz M et al. (2008): Exposure of Fischer 344 rats to a weak power frequency magnetic field facilitates mammary tumorigenesis in the DMBA model of breast cancer
Girgert R et al. (2008): Electromagnetic fields alter the expression of estrogen receptor cofactors in breast cancer cells
Chung MK et al. (2008): Lack of a co-promotion effect of 60 Hz rotating magnetic fields on N-ethyl-N-nitrosourea induced neurogenic tumors in F344 rats
Fedrowitz M et al. (2005): Power frequency magnetic fields increase cell proliferation in the mammary gland of female Fischer 344 rats but not various other rat strains or substrains
Fedrowitz M et al. (2004): Significant differences in the effects of magnetic field exposure on 7,12-dimethylbenz(a)anthracene-induced mammary carcinogenesis in two substrains of Sprague-Dawley rats
McCormick DL et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in B6C3F1 mice
Boorman GA et al. (1999): Chronic toxicity/oncogenicity evaluation of 60 Hz (power frequency) magnetic fields in F344/N rats