EMF-Portal | Modification of tumor promotion in the mouse skin by exposure to an alternating magnetic field

Modification of tumor promotion in the mouse skin by exposure to an alternating magnetic field med./bio.

By: Stuchly MA, McLean JR, Burnett R, Goddard M, Lecuyer DW, Mitchel RE

Published in: Cancer Lett 1992; 65 (1): 1-7

Aim of study (acc. to author)

To investigate if an 60 Hz magnetic field could act as a tumor co-promoter in the SENCAR-mouse model.

Background/further details

DMBA and TPA (synonym PMA) were used to initiate the carcinogenic process and to promote tumor development, respectively. A total of 96 mice were used (2 groups of 48 animals each). Each mouse was treated with a single, subcarcinogenic DMBA dose (10 nmol). One week thereafter a weekly TPA treatment (0.3 µg) over the next 23 weeks was started. One group of animals served as sham-exposed control group. Each day randomly 3 animals of the other group were choosen to be exposed. Tumor development was physically examined each week.

Endpoint

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: repeated daily exposure, 6 h/day, 5 days a week	magnetic flux density: 2 mT unspecified

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	repeated daily exposure, 6 h/day, 5 days a week

Exposure setup

Exposure source	coil(s)
Chamber	acrylic exposure cage/ 0.1 m x 0.25 m x 0.18 m

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2 mT	unspecified	unspecified	-	-

Additional parameter details

The magnetic field in the sham system was less than 0.08 µT

Reference articles

McLean JR et al. (1991): Cancer promotion in a mouse-skin model by a 60-Hz magnetic field: II. Tumor development and immune response

Exposed system:

animal
mouse/SENCAR
whole body

Methods Endpoint/measurement parameters/methodology

Investigated system:

investigation on living organism

Investigated organ system:

skin

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

The percentage of mice with tumors and the mean number of tumor per mouse were statistically significant higher for the exposed group at week 18 of the experiment. However, at week 23 this differences were no longer significant.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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

McLean JR et al. (2003): A 60 Hz magnetic field does not affect the incidence of squamous cell carcinomas in SENCAR mice

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

McLean JR et al. (1997): The effect of 60 Hz magnetic fields on co-promotion of chemically induced skin tumors on SENCAR mice: a discussion of three studies

McLean J et al. (1995): A 60-Hz magnetic field increases the incidence of squamous cell carcinomas in mice previously exposed to chemical carcinogens