AIR POLLUTION COULD TRIGGER LUNG CANCER IN NON-SMOKERS
Research into the dangerous effects of air pollution could lead to approaches to lung cancer prevention
Scientists have discovered a new mechanism through which tiny pollutant particles in the air may trigger lung cancer, even in people who have never smoked. This identification could now be used to develop new prevention measures or even therapies for lung cancer. The particles, which are typically found in vehicle emissions and fossil fuel smoke, are associated with the most common form of lung cancer, accounting for over 250,000 lung cancer deaths each year worldwide.
The research was funded by Cancer Research UK and was carried out by scientists of the Francis Crick Institute and the University College London.
“The same particles in the air that derive from the combustion of fossil fuels, exacerbating climate change, are directly impacting human health via an important and previously overlooked cancer-causing mechanism in lung cells,” said Prof Charles Swanton, chief clinician of Cancer Research UK.
“The risk of lung cancer from air pollution is lower than from smoking, but we have no control over what we all breathe. Globally, more people are exposed to unsafe levels of air pollution than to toxic chemicals in cigarette smoke, and these new data sets link the importance of addressing climate health to improving human health.”
These new findings come from both human and lab research on mutations in a gene known as EGFR. These mutations are seen in about half of people with lung cancer who have never smoked. Exposure to increasing concentrations of airborne particles was linked to an bigger risk of EGFR mutations and lung cancer.
“The risk of lung cancer from air pollution is lower than from smoking, but we have no control over what we all breathe”
In another set of experiments, the Francis Crick team took small samples of normal lung tissue. They found mutations of EGFR and another gene called KRAS, in 18 per cent and 33 per cent of the samples.
“We found that driver mutations in EGFR and KRAS genes, commonly found in lung cancers, are actually present in normal lung tissue and are a likely consequence of ageing,” said Swanton.
“However, when lung cells with these mutations were exposed to air pollutants, we saw more cancers and these occurred more quickly than when lung cells with these mutations were not exposed to pollutants.”
This suggests that air pollution promotes the initiation of lung cancer in cells that already have particular genetic mutations. The next step for researchers will be to discover why some lung cells with mutations become cancerous when exposed to pollutants while others don’t appear to.