Smoking is the main risk factor for lung cancer. Exposure to secondhand smoke can also increase the risk of lung cancer. This is what scientists have known for a long time. What they didn’t know until now is that very small pollutant particles in the air can trigger lung cancer in people who have never smoked.

The finding is based on a survey of more than 400,000 people looking for associations between air pollution and cancer risk.

The researchers performed ultra-deep profiling of 247 normal lung tissue samples and analyzed normal lung tissue from humans and mice following exposure to airborne particulate matter (PM).

They also investigated the consequences of PM on tumor promotion in mouse lung cancer models.

Specifically, research has shown that air pollution can trigger lung cancer in people without a history of smoking, because some pollutant particles in the air can promote changes in cells in the airways.

Pollution affects more and more people

Higher exposure to particulate matter – 2.5 micrometers or smaller in diameter – can cause rapid changes in airway cells that have mutations of a gene called EGFR, which are seen in about half of people with lung cancer who do not never smoked, and another gene linked to lung cancer called KRAS.

This is the conclusion of research carried out by scientists at The Francis Crick Institute in London and other institutions around the world.

“We found that mutations in the EGFR and KRAS genes, commonly found in lung cancers, are actually present in normal lung tissue and are a likely consequence of aging,” explains Dr. Charles Swanton in a press release published by ESMO , researcher at The Francis Crick Institute and chief clinician at Cancer Research UK, who presented the results.

Pollutant particles in the air can promote cell changes

“It has been known for some time that air pollution is associated with the risk of lung cancer, but it was not known how air pollution causes lung cancer. What we found is that exposure to air pollution in both mice and humans results in an inflammatory axis.”

The research findings are important given that many more people are exposed to what the World Health Organization (WHO) would describe as unsafe levels of air pollution.

In fact, it is estimated that almost every person on this planet is exposed to levels of air pollution that the WHO would consider unsafe, he writes MedicalXpress.

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