Why car pollution leads to lung cancer

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Why car pollution leads to lung cancer
Why car pollution leads to lung cancer
13 September, 11:43SciencePhoto: Ukwithny
The connection between small particles that are released into the air during traffic and cancer explains why so many non-smokers are among the sick.

At a conference of the European Society for Medical Oncology in Paris, researchers from the Francis Crick Institute (London) spoke about their discovery, which explains why not only smokers die from lung cancer, according to medicalXpress.

Smoking is still the main cause of lung cancer. But, for example, in the UK, about one in ten gets sick not from cigarettes, but from air pollution. Globally, in 2019 alone, 300,000 people died from lung cancer caused by exposure to fine particles (PM2.5) in polluted air.

The mechanism underlying this dependence was not clear until recently. If smoking or sun exposure directly causes DNA mutations associated with lung and skin cancers, then air pollution does not. Non-smokers with lung cancer tend to have mutations that are found in healthy lung tissue: these are small mistakes that DNA accumulates throughout life and are usually harmless.

British scientists conducted laboratory experiments that showed that fine particles can be a trigger that turns cells with dormant mutations into malignant ones. The researchers studied gene-edited mice that had mutations in the EGFR gene associated with lung cancer. It turned out that when exposed to particles of pollutants, rodents from this group developed cancer more often. The risk has been linked to the inflammatory protein interleukin-1, beta, which is released by the body's immune system in response to exposure to PM2.5. When mice were given protein-blocking drugs, they were less vulnerable to pollutants.

This study sheds light on an accidental discovery by the pharmaceutical company Novartis, whose researchers in clinical trials of a cardiovascular drug found that patients who took the interleukin-1 inhibitor, beta, had a reduced incidence of lung cancer.

The scientists also examined samples of healthy lung tissue taken during biopsies and found that one in five samples had an EGFR mutation. That is, all people have dormant mutations in their cells that can develop into cancer, and the constant inhalation of polluted air increases this likelihood.

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