Two researchers at the University of Hawaii Cancer Research Center have found the causal pathway that leads from the presence of asbestos fibers in the lung to the development of the aggressive and deadly cancer mesothelioma. In a study published in the Proceedings of the National Academy of Sciences, Drs Haining Yang and Michele Carbone demonstrated that the microscopic asbestos fibers which become embedded in lung tissue trigger an inflammatory process that leads to cell mutations. They identified a molecule, HMGB1, which cells release when they are exposed to asbestos. HMGB1 regulates the inflammatory response, triggering the chronic inflammation that promotes tumor growth and over time develops into mesothelioma.
The importance of their work is the confirmation of this causal pathway and understanding of HMGB1’s involvement. In order to design treatment and prevention strategies, doctors must first understand the causal mechanism, so they know what processes to target and how.
Inflammation has long been understood as a contributor to disease processes as varied as heart disease, Alzheimer’s, diabetes, and arthritis. Its involvement in other cancers has been well documented. Recently, researchers have shown that regular consumption of aspirin, which is an anti-inflammatory agent, can slow the growth of colon cancer.
The challenge for prevention of mesothelioma is that once the microscopic asbestos fibers are inhaled and make their way into lung tissue, it is impossible to remove them. The focus instead must be on reducing the embedded fibers’ potential to cause inflammation and therefore disease. Drs Yang and Carbone now believe that by focusing on HMGB1 they have a means to reduce the chronic inflammation. This could lead both to preventing the development of mesothelioma, and for people who already have the disease, slowing its growth. Because mesothelioma is a slow-growing cancer, a treatment that could retard that growth process could prolong lives and significantly improve quality of life.
The work that led to these findings was conducted on mice and hamsters, whose lung tissue responds to asbestos very similarly to humans’ lungs. Their next study will be with humans, in a region of Turkey where the death toll from mesothelioma is the highest on earth. In rural Anatolia and southeastern Turkey, where the soil is saturated with asbestos, and villagers plaster their houses with an asbestos compound, nearly half the population dies of mesothelioma. Drs Yang and Carbone plan to test a variety of medications, including aspirin, to gain a better understanding of the inflammatory process, and how to control it. Their findings are likely to provide new pathways for treatment of this aggressive cancer.
If you or a loved one has received a diagnosis of mesothelioma, and you believe that the exposure to asbestos, no matter how long ago, occurred in your workplace, you will want to consult with an experienced asbestos attorney to determine whether you may have a legal case.