Farmers, painters, hairdressers, firefighters, and first responders to the Sept. 11 World Trade Center attack belong to groups of people whose risk of developing multiple myeloma, a bone marrow cancer, may be greater due to work-related environmental toxins. Agricultural workers may be endangered by the pesticides they work with, while firefighters and first responders face a melting pot of combusted chemicals and other environmental toxins. For researchers, this raises interesting questions, including what specific toxins could be contributing to multiple myeloma development and, because so few people actually develop the disease, are some people predisposed to developing myeloma — is there a genetic link?
Myeloma Research: Environmental Toxins
Researchers are trying to determine which environmental toxins or exposures, such as dust or certain pesticides, could contribute to multiple myeloma.
“We don’t know as much as we would like,” says cancer epidemiologist Anneclaire J. De Roos, PhD, a researcher at the Fred Hutchinson Cancer Research Center in Seattle, Wash. “What we do know is that farmers have an increased risk of developing multiple myeloma, but in terms of the specific types of exposures, there is not enough information to target what pesticide is responsible for that.” Permethrin and chlorinated solvents are among the chemicals being studied for their possible contribution to myeloma.
The problem researchers face, explains De Roos, is that multiple myeloma is relatively rare. That makes it hard to get enough information to establish a firm link between any given exposure and developing myeloma. “Even if you find associations, they are still fairly uncertain at this time,” adds De Roos. The benchmark Agricultural Health Study, which De Roos says is the largest one to look at exposure and health outcomes for agricultural workers, provided an analysis of data from 49,093 people who professionally applied the pesticide permethrin between 1993 and 1997. When examining the data, researchers found a link between the pesticide exposure and the development of multiple myeloma, but this was based on only 15 cases within that population. The researchers concluded that this finding warranted further research into the relationship between multiple myeloma and pesticide exposure.
Myeloma Research: Genetics
One way for scientists to understand these complex relationships is by looking at trends noted in different studies over time. Many smaller studies that point toward the same conclusion support the idea that exposure to environmental toxins put people at risk, but what happens at the individual cell level that causes one person to develop the disease and another to avoid it?
A recent study of changes at the cellular level sought to answer that question. Using the genetic data collected from myeloma patients around the world as part of the International Myeloma Foundation (IMF) Bank on a Cure effort, researchers at the IMF began an analysis at the genetic level.
They found clues to a complex relationship that may be at the heart of myeloma risk: the association between an individual’s genetic ability to process toxins and their exposure to chemicals in their environment.
“We were trying to find out what sort of DNA changes seem to predispose people to get myeloma,” explains Brian Durie, MD, IMF chairman. Genetic differences between individuals were examined to see if there was any pattern that indicated a link between exposure to toxins and risk of myeloma. Researchers found that “patients with myeloma have a type of DNA where they are less able to break down toxins in the environment,” says Dr. Durie.
Durie says that while it is not always possible to know who is at risk in advance of exposure, there is enough evidence to support an overall increased risk from toxic chemicals. Researchers have observed that agricultural workers with multiple myeloma tend to have higher levels of pesticides in their blood than those without myeloma, which also supports the idea that there may be a genetic link affecting the breakdown of toxins. “It’s like piecing a jigsaw puzzle together,” Durie says.
Reducing Multiple Myeloma Risk
Even while researchers continue to explore the question of risk, Durie says individuals and governments can reduce risk by:
- Strictly following current recommendations for the use of pesticides and other potentially toxic chemicals.
- Learning about additional recommendations that may exist for at-risk professions, such as the guidelines published by the IMF for firefighters.
- Advocating for the sale and use of only non-toxic chemicals.
Meanwhile, efforts continue in an attempt to understand how a genetic link explains the way in which environmental toxins may ultimately affect bone marrow.
Last Updated: 6/21/2010