Lung cancer in non-smokers attributed to polluted air
Reducing air pollution is also crucial for health, says a study.
Over 90% of the world's population is exposed to what the WHO considers to be excessive levels of fine particulate pollutants.
Like a “hidden killer”, air pollutants can cause lung cancer in non-smokers through a mechanism unveiled Saturday in a study that marks a “significant step for science – and society” according to experts.
Already involved in climate change, fine particles – less than 2.5 microns, for comparison, the average diameter of a human hair is 60 microns – are responsible for cancerous changes in cells of the respiratory tract, according to scientists from the Francis-Crick Institute and University College, London.
There are fine particles in vehicle exhaust, vehicle brake dust and fossil fuel smoke.
Found in vehicle exhaust, brake dust and fossil fuel fumes, fine particles are a hidden killer, Charles Swanton of the Agence France-Presse (AFP) told Agence France-Presse (AFP). x27;Francis Crick Institute. The latter is responsible for presenting the research, not yet peer-reviewed, at the annual congress of the European Society for Medical Oncology, which takes place until September 13, in Paris.
While air pollution has long been suspected, we weren't sure whether or how this pollution directly caused lung cancer, Professor Swanton explained.
The researchers first explored data from more than some 450,000 residents of England, South Korea and Taiwan, and showed that exposure to increasing concentrations of fine particulate matter was linked to an increased risk of lung cancer.
The major discovery is that of the mechanism by which these pollutants can trigger lung cancer in non-smokers.
Through laboratory studies on mice, researchers have shown that particles caused changes in two genes (EGFR and KRAS), already linked to lung cancer.
They then analyzed 247 samples of healthy human lung tissue, never exposed to tobacco carcinogens or heavy pollution. Mutations in the EGFR gene appeared in 15% of the samples, alterations in KRAS in 53%.
Alone, these mutations are probably not enough to lead to cancer. But when you expose a cell to pollution, it probably stimulates some sort of inflammatory reaction, and if the cell harbors a mutation, it will form cancer, Professor Swanton sums up.
This is a deciphering of the biological mechanism of what was an enigma, but quite confusing, recognizes this chief medical officer of Cancer Research UK, the main contributor to the study.
Traditionally, it was thought that exposure to carcinogenic factors, such as those from cigarette smoke or pollution, caused genetic mutations in cells, making them tumorous and causing them to proliferate.
For Suzette Delaloge, director of the cancer prevention program at the Gustave-Roussy Institute, this is quite revolutionary because there was practically no demonstration of this alternative carcinogenesis before. /p>
Traditionally, exposure to cigarette smoke was thought to cause genetic mutations in cells, making them tumorous and causing them to proliferate.
This study is a pretty big step for science – and for society too, I hope, the oncologist, who was in charge of discussing the study at the congress, told AFP. This opens a great door for knowledge, but also for prevention.
The next step will be to understand why certain altered lung cells become cancerous after exposure to pollutants, according to Professor Swanton .
This study confirms that reducing air pollution is also crucial for health, insist several researchers.
We have the choice to smoke or not, but not to x27;air we breathe. As probably five times more people are exposed to unhealthy levels of pollution than tobacco, this is a major global problem, Professor Swanton quipped.
More than 90% of the world's population is exposed to what the WHO considers to be excessive levels of fine particulate pollutants.
This research also raises hopes for new approaches to prevention and treatment.
To detect and prevent, Suzette Delaloge is considering several avenues, such as the personal assessment of our exposure to pollutants, detection – not yet possible – of the mutation EGFR genetics, etc.
According to Tony Mok, from the University of Hong Kong, quoted in an ESMO press release, this research, as intriguing as it is promising[…] make it possible to one day look for pre-cancerous lesions in the lungs using imaging and then try to treat them with drugs like inhibitors of cancer. #x27;interleukin-1.
Professor Swanton imagines what molecular prevention of cancer could look like in the future ncer, with a pill, maybe every day, to reduce the risk of cancer in high-risk areas.