Air pollution can trigger lung cancer – even in people who have never smoked, according to the latest research. Experts say inflammation in the lungs, caused by tiny toxic particles in the air, promotes the growth of cells which carry cancer-causing mutations.
It is hoped the findings could pave the way for a cheap pill that could be taken by people who live in cities, where pollution from traffic and industrial plants is highest.
Professor Charles Swanton, Cancer Research UK’s chief clinician, said such a treatment is probably ten to 20 years away.
But he added: “If you could take a tablet one day that could interfere with a specific part of the pathway without causing any toxicity, as we do for statins and cardiovascular disease, there is hope for the future.”
Toxic particles have been linked to a range of health conditions, including asthma, heart disease and dementia. But scientists were previously baffled as to how pollution could increase the risk of lung cancer.
Prof Swanton and his team discovered PM2.5 particles – which measure around three per cent of the width of a human hair – cause the lung inflammation which can “wake up” cells carrying dangerous mutations and encourage them to develop into tumours.
They looked at a type of lung cancer linked to mutations in the EGFR gene, which often affects non-smokers.
Data from more than 400,000 people in the UK and Asia showed higher rates of the cancer in areas where air pollution levels were higher.
And tests showed mice carrying EGFR mutations were more likely to develop tumours when exposed to air pollution.
Prof Swanton said: “Cells with cancer-causing mutations accumulate naturally as we age, but they are normally inactive. We’ve demonstrated air pollution wakes these cells up, encouraging them to grow and potentially form tumours.”
The CRUK-funded study, in journal Nature, was led by the Francis Crick Institute and University College London.
Around 6,000 non-smokers die of lung cancer each year in the UK. But smoking is still the biggest cause of the disease, accounting for almost three-quarters of the 48,500 cases diagnosed every 12 months.
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