Scientists have known for decades that asbestos is a major carcinogen. Its long, pointed fibers can lead to chronic inflammation that could cause cancer to develop.
Researchers from the University Hospitals of Zurich, Geneva, and Toronto (in Canada), in collaboration with their counterparts from the University of Fribourg and ETH Zurich, have found the mechanism by which fibers damage the body and result in cancer.
“Chronic exposure to asbestos triggers a type of tissue repair,” said lead study author Emanuela Felley-Bosco. “The immune system goes out of balance and is no longer strong enough to combat tumour formation.”
The research was published in Oncogene, a peer-reviewed journal on cancer.
How mesothelioma develops
Chemically, asbestos is practically harmless to the body. What makes it rather worrying is the potential of its fibers to cause micro-injuries in tissue.
Asbestos makes its way into the mesothelium, a cell layer bordering organs in the body, after entering into the lungs. Its long, pointed fibers remain stuck in this region because the lymphatic system lacks the ability to clear them effectively.
While in the mesothelium, the fibers can injure tissue repeatedly and this can result in cancer.
Researchers made use of mice for this study. They injected into the abdominal cavity of the animals, which also have mesothelium tissue, asbestos fibers.
Micro-injuries caused by the fibers induced an immune reaction. Inflammatory signals were transmitted to call white blood cells into action.
Inflamed mesothelium tissue showed the activation of tissue repair signaling pathways. This encourages the proliferation of cells, which can serve to encourage tumor growth.
In addition, the research team observed a buildup of RNA mutations. This made it to hypothesize that these mutations are among the factors that reduce the immune response for tissue repair. This gives room for tumors to grow more easily and result in cancer.
A similar mechanism to that observed in the mice exists in humans, the researchers said. This was going by an analysis carried out using data obtained from a gene bank.
Tumors of patients with poor outcomes produced high amounts of enzymes that are linked to RNA mutations.
Researchers in this study said that their results could help for early cancer diagnosis. They stated that the research will be valuable for detecting early signs of inflammation that could result in the disorder.
The results could also contribute to a better understanding of other conditions and forms of cancers related to chronic inflammation. These disorders include Crohn’s disease and ulcerative colitis.
Felley-Bosco said that the findings will help in the development of a more clear-cut therapy for mesothelioma as well.
“A therapy against immune system inhibitors is a promising approach,” she said. “Similar therapeutic approaches to treating mesothelial cancer are already being used today.”
Researchers are already working in the UK, Switzerland, and Spain to find out how immunotherapy could help deal with advanced-stage mesothelial cancer.