Uncovering how air pollution causes lung cancer
Cigarette smoking is the number one risk factor for lung cancer. Exposure to second-hand smoke can also increase the risk of lung cancer. This is what scientists have known for a long time. What they did not know until now is that very small pollutant particles in the air may trigger lung cancer in people who have never smoked. The discovery is based on research carried out on more than 400 000 people in search of associations between their air pollution and cancer risk. Researchers from the EU- and European Research Council-funded PROTEUS, THESEUS, PLOIDYNET, CHROMAVISION and WHOLENICHE projects performed ultra-deep profiling of 247 normal lung tissue samples and analysed normal lung tissue from humans and mice following exposure to the air pollutant particulate matter (PM). They also investigated the consequences of PM on tumour promotion in mouse lung cancer models. The findings were presented at the European Society for Medical Oncology (ESMO) Presidential Symposium in Paris in September 2022. Specifically, the research showed that air pollution can trigger lung cancer in people with no history of smoking because some air pollutant particles may promote changes in cells in the airways.
Non-smokers at risk
As reported in a news item posted on ‘CNN’, more exposure to airborne PM – at 2.5 micrometres in diameter or smaller – can drive rapid changes in airway cells that have mutations in a gene called EGFR, which are seen in about half of people with lung cancer who have never smoked, and another gene linked to lung cancer called KRAS. This is according to the research conducted by scientists at The Francis Crick Institute in London and other institutions around the world. “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,” Dr Charles Swanton, a scientist at The Francis Crick Institute and chief clinician at Cancer Research UK who presented the findings, explains in a news release published by ESMO. In a video released by ESMO, Dr Swanton notes: “It’s been known for some time that air pollution is associated with lung cancer risk, but it hasn’t been known how air pollution causes lung cancer. … What we found is that air pollution exposure in both mice and humans results in an inflammatory axis.” The research findings are important considering that many more people than smokers are exposed to what the World Health Organization (WHO) would describe as unsafe levels of air pollution. In fact, it is estimated that nearly every single person on this planet (95 %) is exposed to levels of air pollution that WHO would consider unsafe. “I think this is an urgent mandate to lower pollution levels,” remarks Dr Swanton. “And of course, climate health and human health are intimately linked.” The research was supported by PROTEUS (Predicting Routes Of Tumour Evolution driven by Unstable genomes and Selection), THESEUS (Tumour Heterogeneity and Somatic Evolution of Unstable cancer genomes), PLOIDYNET (The impact of chromosomal instability on health: Molecular causes and consequences of aneuploidy), CHROMAVISION (Super-resolution visualisation and manipulation of metaphase chromosomes), and WHOLENICHE (Hold it or let it go: a niche decision on cancer growth). The THESEUS, PLOIDYNET and CHROMAVISION projects have ended. WHOLENICHE and PROTEUS are ongoing. For more information, please see: CHROMAVISION project website PROTEUS project THESEUS project PLOIDYNET project WHOLENICHE project
Keywords
PROTEUS, THESEUS, PLOIDYNET, CHROMAVISION, WHOLENICHE, particulate matter, air pollution, lung cancer, lung, cancer