Authors

Paulraj R, Behari J. Effects of low level microwave radiation on carcinogenesis in Swiss Albino mice. Mol Cell Biochem. Nov 18, 2010.  Ahead of print.

Background
Continuous exposure to non-ionizing radiation such as radiofrequency (RF) and microwave radiation (MW) generates electromagnetic fields (EMF) that can interact with biological systems and may promote cancer growth.  Cancer growth is believed to come about in two stages; stage one is where a cells’ DNA is damaged beyond repair and stage two is where conditions promote the formation of malignant cells.  This study investigates whether EMF promotes stage two in cancer formation and growth, by exposing mice to EMF after they have been challenged with two carcinogens; a skin cream that initiates skin cancer and cells from a tumour injected into the stomach area.      

Objective
The objective of this study was to determine the effects of EMF on tumour development after an initial carcinogen was administered.

Methods
Several different groups of Swiss albino mice (7-8 week old males) were used in this study and the different experimental groups are outlined below: 

Group A experiment asked the question whether mice exposed to RF and MW frequency radiation experienced an increase in skin cancer with or without application of skin cancer cream.

  1. Group A1 (control group) were sham irradiated; these mice were treated the same as the other mice but not exposed to anything.
  2. Group A2 (carcinogen skin cream) received a single dose of the skin cream.
  3. Group A3 (carcinogen skin cream plus RF radiation exposure) received a single dose of the skin cream and then two weeks later were exposed to 112 MHz amplitude modulated at 16 Hz (frequency of many electronic devices) 2 hours/day, 3 days a week for 16 weeks.
  4. Group A4 (carcinogen skin cream plus MW radiation exposure) received a single dose of the skin cream and then two weeks later were exposed to 2.45 GHz (frequency of microwaves) 2 hours/day, 3 days a week for 16 weeks.
  5. Group A5 (RF radiation exposure only) were exposed to 112 MHz amplitude modulated at 16 Hz (frequency of many electronic devices) 2 hours/day, 3 days a week for 16 weeks.
  6. Group A6 (MW radiation exposure only) were exposed to 2.45 GHz (frequency of microwaves) 2 hours/day, 3 days a week for 16 weeks.
  7. Group A7 (positive control group; carcinogen skin cream plus croton oil) received a single dose of the skin cream and then after two weeks the mice received an application of croton oil twice a week for 16 weeks.  Croton oil is known to promote tumour growth.

After the experiment, mouse skin was examined carefully under light and any tumours were measured with callipers.

 

Group B experiment asked the question whether mice exposed to RF and MW frequency radiation experienced an increase in tumour cells in the abdominal cavity.   

  1. Group B1 (injected with tumour cells) were injected with tumour cells into their abdominal cavities and then were sham irradiated in the chamber of the 112 MHz amplitude modulated at 16 Hz device for 2 hours/day for 14 days.  This means that the mice experienced the same stressful conditions as the irradiated mice but without exposure to radiation.  
  2. Group B2 (injected with tumour cells plus RF radiation exposure) were injected with tumour cells into their abdominal cavities and then were irradiated at 112 MHz amplitude modulated at 16 Hz (RF frequency radiation) for 2 hours/day for 14 days. 
  3. Group B3 (injected with tumour cells) were injected with tumour cells into their abdominal cavities and then were sham irradiated in the chamber of the 2.45 GHz (MW frequency radiation) for 2 hours/day for 14 days.  This means that the mice experienced the same stressful conditions as the irradiated mice but without exposure to radiation. 
  4. Group B3 (injected with tumour cells plus MW radiation exposure) were injected with tumour cells into their abdominal cavities and then were irradiated in the chamber of the 2.45 GHz (MW frequency radiation) for 2 hours/day for 14 days.

The cells from the abdominal cavities of the mice were taken out with a syringe and counted to see if one group had more cells than another group.

Results
The researchers found no tumours on the skin of the group A mice expect for Group A7 (the positive control) where optimum conditions were designed to promote the formation of tumours.  However, in group B, there was a slight increase in the number of cancer cells extracted from the abdominal cavity of mice treated with EMF radiation compared to mice that were not exposed.  However, this result was statistically insignificant, which means that this slight increase could have occurred randomly with the number of mice that were subjected to the experiment.   

Interpretation and Limitations
The researchers hypothesize that the levels and duration of RF and MW radiation that the mice were exposed to were too low to contribute to tumour growth and development.   

Conclusion
This study demonstrates that exposure to EMF (RF or MW) does not promote cancer growth or development after exposure to a carcinogen. 


Home             Links              Sitemap               Contact Us
© McLaughlin Centre for Population Health Risk Assessment