Japanese researchers believe they may be on the path to developing a method to help keep people who have been exposed to asbestos from developing deadly malignant mesothelioma.
Mesothelioma is an extremely rare but usually lethal cancer caused by exposure to asbestos fibers. Many people were unknowingly exposed to these fibers in their workplaces.
Because there is currently no known way to reduce the risk of malignant mesothelioma in people who have already been exposed, their bodies are like ticking time bombs. But researchers at Nagoya University Graduate School of Medicine say there may be a way to change that by reducing the amount of iron in their systems.
How Asbestos Causes Mesothelioma
Although the exact mechanism by which asbestos fibers trigger mesothelioma in some people is not fully understood, researchers know that the process is multifactorial.
One of those factors is inflammation caused by the shards of asbestos which lodge in the tissue and stay there after they are inhaled or ingested. In some cases, chronic inflammation at the cellular level can alter the cells and trigger mesothelioma.
Another factor is iron. Even though people need a certain amount of iron to be healthy, people and laboratory animals with mesothelioma have an overload of iron in their systems suggesting that iron has an impact on cancer development.
A third potential mesothelioma trigger is oxidative stress, an imbalance between the production of free radicals and the body’s ability to modify their toxic effects with antioxidants.
Removing Iron to Reduce Mesothelioma Risk
In their laboratory experiment, the Japanese team simulated a pre-cancerous state in rats by exposing them to asbestos. As expected (and like asbestos-exposed people), the rats developed inflammation, increased levels of iron, and oxidative stress.
Then, the research team “treated” the rats by injecting a chelating or iron-removing agent called desferal into their abdomens, where peritoneal mesothelioma grows.
In an article in Cancer Science, the team reports that the desferal “significantly decreased” the formation of scarring and thickening of the peritoneum, the amount of iron in the tissues, and the level of a key indicator of oxidative stress. All of these can be precursors of mesothelioma.
Iron May “Feed” Growing Mesothelioma Cells
Another key finding from the experiment was the fact that rat peritoneal mesothelioma cells were more dependent on iron to grow and proliferate than were the normal mesothelial cells.
In a summary of the findings, author Jiang Li concludes that iron elimination after asbestos exposure could work in several ways to reduce mesothelioma risk.
“Iron elimination from the mesothelial environment can confer dual merits for preventing asbestos-induced mesothelial carcinogenesis by suppressing inflammation and mesothelial proliferation simultaneously,” writes Dr. Li.
Although asbestos is heavily regulated in the US, about 2,500 new cases of malignant mesothelioma are still diagnosed each year.
Li, J, et al, “Dual preventive benefits of iron elimination by desferal in asbestos-induced mesothelial carcinogenesis”, April 18 2016, Cancer Science, Epub ahead of print