Science

Lung cancer in non-smokers: Researchers find cause and possible prevention

Fossil fuel use
Possible cause of lung cancer found in non-smokers

Burning coal, oil, and gasoline not only harms the climate, but also produces exhaust fumes that increase the risk of lung cancer, even for non-smokers. Researchers are now investigating why this is so. And they find a possible way to prevent it.

Scientists from the UK have presented an explanation why non-smokers also develop lung cancer. Researchers at the Francis Crick Institute and University College London used patient records, animal studies and sample collection to find out how lung cancer is linked to fossil fuel exhaust air pollution. They presented the results of their study, which has not yet been published in a specialized journal, at the annual meeting of the European Society for Medical Oncology in Paris.

Cancer researcher Charles Swanton of the Francis Crick Institute, who participated in the study, told the AFP news agency that a link between air pollution and an increased risk of lung cancer has long been suspected. “But we didn’t really know if pollution directly causes lung cancer, and if so, how.”

It has long been believed that exposure to carcinogens, such as cigarette smoke or vehicle fumes, causes DNA mutations that lead to cancer. According to Swanton, this is not consistent with the fact that studies have shown that, on the one hand, DNA mutations can occur without causing cancer, and on the other hand, that most carcinogens in the environment do not cause mutations.

Changes in some genes

Swanton and his colleagues studied the files of more than 460,000 patients in England, South Korea and Taiwan. The analysis showed that people who are more exposed to PM2.5 particulate matter have an increased risk of mutations in the EGFR gene, Swanton said.

In the lab, his research team showed in mice that PM2.5 particles induce changes in the EGFR and KRAS genes, both of which are associated with lung cancer. Finally, the research team studied about 250 lung samples from people who had never been exposed to air pollution or tobacco smoke. Although their lungs were healthy, 18 percent of the samples had mutations in the EGFR gene and 33 percent had mutations in the KRAS gene.

“They just sit there,” Swanton said of the genetic changes, which he says increase with age. “On their own, they probably aren’t enough to cause cancer.” However, if a cell is exposed to air pollution, for example, it can trigger a “wound-healing response” with inflammation, Swanton explained. If the affected cell is affected by the corresponding gene mutation, cancer develops.

Tablet could prevent future cancer

In addition to explaining the development of lung cancer, Swanton and colleagues also developed a method for preventing lung cancer. In experiments on mice, they showed that the messenger substance interleukin 1 beta, which triggers the inflammatory process, can be stopped by an antibody.

According to Swanton, this can prevent the development of lung cancer in advance. He hopes that on this basis it will be possible to develop “molecular cancer prevention”, for example in the form of pills that people can take daily as a precautionary measure.

Cancer researcher Suzette Delalog, who was not involved in the study, said the study was “a pretty big step for science and hopefully for society.” According to Delalog, this opens “an enormous door to both knowledge and new ways to prevent” cancer.

(This article was first published on Sunday, September 11, 2022)

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