Air pollution can cause lung cancer in non-smokers, a new study finds

You don’t smoke, hoping that will keep you safe from lung cancer, but that may not be the case according to a new study.

A new system has been identified through which tiny pollutant particles present in the air may cause lung cancer in people who have never even touched a cigarette. That's according to a press release by the European Society for Medical Oncology published on Saturday.

Vehicle exhaust and smoke from fossil fuels

The invisible but mighty particles are typically found in vehicle exhaust, and smoke from fossil fuels, and are associated with non-small cell lung cancer risk. They are responsible for over 250,000 lung cancer deaths globally per year.

“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 Charles Swanton, the chief clinician at the Francis Crick Institute and 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 link the importance of addressing climate health to improving human health.”

It's due to mutations in two genes, EGFR and KRAS, which are seen in about half of people with lung cancer who have never smoked.

The researchers undertook a study of nearly half a million people living in England, South Korea, and Taiwan. They found a connection between an increased risk of lung cancer and EGFR and KRAS mutations.

“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 aging. In our research, these mutations alone only weakly potentiated cancer in laboratory models," 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, suggesting that air pollution promotes the initiation of lung cancer in cells harboring driver gene mutations. The next step is to discover why some lung cells with mutations become cancerous when exposed to pollutants while others don’t," he added.

Reducing air pollution

Meanwhile, Tony Mok, from the Chinese University of Hong Kong, who was not involved in the study, said the research opens doors to using the highly sensitive EGFR profiling on blood or other samples to find non-smokers who are predisposed to lung cancer.

However, before looking at early diagnosis, he notes the importance of reducing air pollution to lower the risk of lung diseases, including cancer.

“We have known about the link between pollution and lung cancer for a long time, and we now have a possible explanation for it. As consumption of fossil fuels goes hand in hand with pollution and carbon emissions, we have a strong mandate for tackling these issues – for both environmental and health reasons,” Mok said.