"Car fumes awaken dormant mutations in lung cells and tip them into a cancerous state and helps explain why so many non-smokers develop lung cancer and is a “wake-up call” about the damaging impact of pollution on human health". Thank you TV host Betsy Rosenberg!
I may be biased yet ICE fumes nearly took me out in 1995. I survived and advocate clean transportation with clean materials and fully recyclable vehicles on land, water and air.
Smoking remains the biggest cause of lung cancer, but outdoor air pollution causes about one in 10 cases in the UK, and an estimated 6,000 people who have never smoked die of lung cancer every year. Globally, about 300,000 lung cancer deaths in 2019 were attributed to exposure to fine particulate matter, known as PM2.5, contained in air pollution.
However, the biological basis for how air pollution causes cancer has remained unclear. Unlike smoking or sun exposure, which directly cause DNA mutations linked to lung and skin cancer, air pollution does not cause cancer by triggering such genetic changes.
Instead, those with non-smoking lung cancer tend to carry mutations that are also seen in healthy lung tissue – small errors that we accumulate in our DNA throughout life and which normally remain innocuous.
“Clearly these patients are getting cancer without having mutations, so there’s got to be something else going on,” said Swanton, who is also Cancer Research UK’s chief clinician. “Air pollution is associated with lung cancer but people have largely ignored it because the mechanisms behind it were unclear.”
The latest work unveils this mechanism through a series of meticulous experiments showing that cells carrying dormant mutations can turn cancerous when exposed to PM2.5 particles. The pollutant is the equivalent of the ignition spark on a gas hob.
In laboratory studies, Swanton’s team showed that mice that had been engineered to carry mutations in a gene called EGFR, linked to lung cancer, were far more likely to develop cancer when exposed to the pollutant particles. They also revealed that the risk is mediated by an inflammatory protein, called interleukin-1 beta (IL1B), released as part of the body’s immune response to PM2.5 exposure. When the mice were given drugs to block the protein, they were less vulnerable to the pollutants.
The work explains a previous incidental finding in a clinical trial of a heart disease drug, made by Novartis, that people on the drug – an IL1B-inhibitor – had a marked reduction in lung cancer incidence. This could pave the way for a new wave of cancer-preventing medicines, Swanton said.
The team also analysed samples of healthy lung tissue, taken during patient biopsies, and found that the EGFR mutation was found in one in five of the normal lung samples. This suggests that we all carry dormant mutations in our cells that have the potential to turn into cancer – and chronic exposure to air pollution increases the odds of that happening.
Source: The Guardian https://www.theguardian.com/science/2022/sep/10/cancer-breakthrough-is-a-wake-up-call-on-danger-of-air-pollution