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HEADLINE: LEUKEMIA: Research suggests potential damage caused by low frequency electromagnetic fields

BODY:
The effect of extremely low frequency electromagnetic fields (ELF-EMF), such as those emitted around high-voltage transmission lines, on human health is controversial.

Some studies suggest an association between exposure to ELF-EMF and incidence of leukemia, although little direct evidence exists that exposure causes damage to biological molecules.

A new study, published in Cancer Cell International, presents experimental evidence to show that extremely low frequency electromagnetic fields can have a potentially damaging effect on the process of cell division in (already) radiation-injured cells, which could lead to them becoming cancerous. Cell division and the growth cycle rely on two major events. The first involves the replication of the cell's genetic material (DNA). The second involves cell separation into two daughter cells. These steps are separated by two pauses or "gaps"; the first occurs after cells have divided, but before the next round of DNA synthesis (G1) and the second between DNA synthesis and division (G2).

These "gaps" allow the cell to take stock of each stage of the process before progressing to the next. The checkpoint in G1 prevents cells from duplicating their DNA if conditions are unfavorable, while the checkpoint in G2 stops cells from dividing when damage has occurred to the chromosomes (DNA). These checkpoints effectively police the process of cell division so that risk of damaged cells replicating is minimized.

When the molecules involved in cell division are damaged by ionizing radiation, for example, it can lead to uncontrolled growth and the development of cancer. The research in Cancer Cell International examines the effects of combined ELF-EMF and ionizing radiation on human cells. The researchers could not find any change in the process of cell division in cells exposed to ELF-EMF alone, but exposure to ionizing radiation predictably caused the process of division to slow down as the cells were held at each checkpoint in order to repair the damage.

It was anticipated that the combined effect of ELF-EMF and ionizing radiation would further slow down the cell cycle. However, cell division was slightly faster in 12 out of 20 experiments, but never slower.

It is well known that ionizing radiation can itself cause cancer, but it seems that ELF-EMF makes the cells push on into division where errors become compounded. The researchers suggested that ELF-EMF may interfere with the G2 checkpoint that normally stops damaged cells entering division before they have had the opportunity to repair the damage, increasing the chances of them becoming cancerous.

The study is clearly at a preliminary stage; however, the researchers hope that this will open up a new line of investigation and help to understand the risks associated with ELF-EMF, for example, suspected in communities living in close proximity to high voltage transmission lines.

This article was prepared by Cancer Weekly editors from staff and other reports.