Written By: Muskan Gupta | Published : June 8, 2026 4:20 PM IST
Lung cancer (Image AI Generated)
One of the largest international studies to date has shown that air pollution and smoke can "awaken" dormant cancer-causing mutations that are already present in the body and lead to an increased risk of lung cancer even among nonsmokers.
The results have been generated by the Sherlock-Lung study, which is one of the largest studies of lung cancer in never-smokers in the world. The study was published in the prestigious paper in the journal Nature in July 2025 and the authors were scientists from various parts of the world and the United States, Europe and Asia. The team studied 871 people without a history of smoking in their lungs in 28 countries around the world.
Scientists long thought that cancer is primarily caused by the direct damage from harmful substances to DNA, which would lead to additional mutations. But this study indicates there are other mechanisms by which air pollution can contribute to cancer, too. Tiny bits of dust can inflame the lungs, providing a breeding ground where dormant mutations will grow into cancerous tumors, rather than mutation having to happen anew.
They discovered that individuals exposed to higher concentrations of fine particulate matter (PM2.5), the tiny particles of pollution released by vehicle exhaust, industrial dust and other activities had a much higher number of cancer-associated genetic alterations in their lung tumors. They were also more likely to have mutations in the TP53 gene, which is a frequently seen cancer-causing gene associated with cancers of tobacco.
The study also found a correlation between increased pollution exposure and the shortening of the protective caps at the ends of chromosomes called telomeres. Telomeres that are shorter than normal will be associated with older cells age and higher cancer possibility. They found it was clear that there was a dose-response relationship; as the pollution level rose, so do the number of harmful genetic changes observed.
Researchers were surprised to find that the secondhand smoke was less effect on cancer-causing mutations than air pollution. Exposure to both passive smoke and total ambient air pollution led to an increased level of mutation, but this appeared to be weaker than the association with cancer-promoting gene signatures associated with passive smoke exposure.
The results are significant as they provide insights to understand why the number of never-smokers being identified with lung cancer is on the rise, experts say. With no history of smoking, lung cancer is now an important public health problem for all of the world, representing 10 25% of lung cancer diagnosed today.
The study emphasizes the need to enhance the air quality and pollution exposure. Fewer such policies, cleaner fuels and improved air quality monitoring may reduce the cancer risk of millions of people worldwide, researchers say.
