A New View of ELF-EMFs
Tenenbaum, David J., Environmental Health Perspectives
Are They Linked with Cancer Promotion?
The debate over a possible link between cancer and extremely low frequency electromagnetic fields (ELF-EMFs) began with a 1979 study that found excess cancer in people who lived near large electrical wires. It has continued through subsequent in vitro, in vivo, and epidemiological studies that often produced conflicting results. In this issue, Gang Chen of the Department of Pediatrics and Human Development at Michigan State University and colleagues used an experimental model developed to test cancer-promoting chemicals to examine whether ELF-EMFs might play a role in cancer promotion [EHP 108:967-972].
The development of cancer is a multistage process. During normal development, immature cells undergo a process called differentiation in which they become highly specialized (developing, for instance, into red blood cells) and are less able to continue proliferating. In the first stage of cancer, initiation, a cell's DNA is damaged through mutation, causing a differentiated cell to resemble an immature one, in effect reversing the process of differentiation. In the second stage, promotion, normal cellular controls go awry, and the mutated cell multiplies. ELF-EMFs are too weak to kill cells or (most scientists agree) to cause mutations and thus initiate cancer. However, they could play a role during the promotion stage of cancer, which involves so-called epigenetic mechanisms (those that affect gene expression rather than gene structure) and induce cancer in cells that have already mutated.
In the laboratory, differentiation--which can be stimulated by chemical treatment--can transform initiated cells into mature cells, converting cells that had started to become cancerous into normal-seeming adult cells. In this case, differentiation seems to be a healing process that nullifies the mutation. …