Study Links Air Pollution to Lung Cancer Mutations in Non-Smokers

A recent study published in Nature has revealed significant findings regarding the alarming increase in lung cancer cases among individuals who have never smoked. Conducted by researchers from the University of California San Diego and the National Cancer Institute (NCI), the study highlights the role of air pollution and certain environmental exposures in contributing to genetic mutations associated with lung cancer in non-smokers. The research was published on July 2, 2025, and indicates that as tobacco usage declines globally, lung cancer incidents in non-smokers are rising disproportionately, particularly among women of Asian descent in East Asian countries compared to their Western counterparts.

According to Dr. Ludmil Alexandrov, a co-senior author and professor of bioengineering and cellular and molecular medicine at UC San Diego, "Our research shows that air pollution is strongly associated with the same types of DNA mutations we typically associate with smoking." This assertion is grounded in the analysis of lung tumors from 871 never-smokers across diverse regions, including Africa, Asia, Europe, and North America, utilizing whole-genome sequencing to uncover distinct patterns of DNA mutations, termed mutational signatures.

The study identified a 3.9-fold increase in a mutational signature typically linked to tobacco smoking among individuals residing in polluted areas, along with a 76% increase in another signature associated with aging. These findings raise critical concerns regarding the long-term health impacts of air pollution, suggesting that it may not only exacerbate existing health issues but also create new ones for never-smokers.

Dr. Maria Teresa Landi, an epidemiologist at the NCI and co-senior author of the study, emphasized the significance of separating the data of smokers from non-smokers in lung cancer research. She stated, "Most previous lung cancer studies have not separated data of smokers from non-smokers, which has limited insights into potential causes in those patients. We have designed a study to collect data from never-smokers around the world and use genomics to trace back what exposures might be causing these cancers."

In addition to air pollution, the researchers noted that aristolochic acid, found in certain traditional Chinese herbal medicines, poses another risk factor for lung cancer in non-smokers. This carcinogen has been linked to various cancers previously, but its potential link to lung cancer is newly established. The research indicates that inhalation of these herbal medicines could inadvertently heighten cancer risk.

Moreover, the study revealed a new mutational signature present in the lung cancers of most never-smokers—its cause remains unidentified but is absent in smokers, indicating that there might be previously unrecognized environmental or biological factors at play.

The researchers plan to expand their investigation to include lung cancer cases from Latin America, the Middle East, and additional regions of Africa. They aim to study the potential impacts of marijuana and e-cigarette use among young non-smokers, along with other environmental risks such as radon and asbestos. This comprehensive approach aims to gather more nuanced data on pollution and its ramifications on public health, particularly for vulnerable populations.

In conclusion, this pivotal study underscores the urgent need for public health initiatives aimed at mitigating air pollution's impact and furthering our understanding of lung cancer in non-smokers. As Dr. Alexandrov stated, "This is an urgent and growing global problem that we are working to understand regarding never-smokers." With the identification of these genomic links, there is an opportunity not only for better prevention strategies but also for targeted research into the environmental factors contributing to this troubling health trend.