The researchers hypothesized that when inhaled, PM2 5 The particles, which measure about 3% the width of a human hair, trigger an alarm response in the lungs, causing inflammation and activation of sleeper cells that carry the cancer-causing mutations. To test their hypothesis, the team exposed mice using EGFR-mutant cells to air pollution concentrations typically found in cities, and found that exposed animals were more likely to develop lung cancer than unexposed mice.
“Our study fundamentally changed how we view lung cancer in people who have never smoked,” noted lead researcher Charles Swanton (Francis Crick Institute, London, UK). Cells with cancer-causing mutations naturally accumulate as we age, but they are usually inactive. We’ve demonstrated that air pollution awakens these cells in the lungs, encouraging them to grow and possibly become tumors.”
Lung cancer is also not the only cancer implicated in these findings. The research team believes that their model of environmental factors that activate cells that carry cancer-causing mutations could be applicable to other types of cancer elsewhere in the body.
“According to our analysis, levels of air pollution increase the risks of lung cancer, mesothelioma, and cancer of the mouth and throat,” co-first author, Emilia Lim (Francis Crick Institute) commented. “this is [finding] It suggests a broader role for cancers caused by inflammation, which are caused by a carcinogen such as air pollution.”
The researchers also hypothesize, on the basis of results from the preclinical part of the study, that blocking the lungs’ alarm response to PM2 5 It may prevent this type of cancer from developing completely.
“The mechanism we identified could eventually help us find better ways to prevent and treat lung cancer in non-smokers,” Swanton explained. “If we can prevent cells from growing in response to air pollution, we can reduce the risk of lung cancer.”
Co-first author William Hill (Francis Crick Institute) agreed. “Finding ways to prevent or reduce inflammation from air pollution would go a long way in reducing lung cancer risk in people who have never smoked, as well as urgently reduce people’s overall exposure to air pollution.”
However, the most urgent precautionary measure required by the results of this study is to reduce air pollution on a global scale in order to protect public health.
Expert Jonathan Samet (Colorado College of Public Health, Aurora, CO, USA) commented: “In 2013, the International Agency for Research on Cancer of the World Health Organization classified outdoor air pollution in general, and airborne particles in particular, as carcinogenic to humans. “. The burden of cancer from air pollution is significant; Swanton and colleagues added to the evidence supporting tighter air pollution control.”
date of publication
Published: September 15, 2022
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