Air Pollution and Environmental Factors Linked to Lung Cancer in Never-Smokers

Recent research highlights a significant connection between air pollution, traditional herbal medicines, and other environmental exposures with the development of lung cancer in individuals who have never smoked. Traditionally, lung cancer has been primarily associated with tobacco use; however, as smoking rates decline globally, cases among never-smokers are becoming increasingly common. Notably, this trend is disproportionately observed among women and individuals of Asian descent, particularly in East Asia.

A comprehensive study published in Nature by researchers from the University of California San Diego and the National Cancer Institute (NCI) has provided compelling genomic evidence linking environmental factors to this rise. The study reveals that air pollution contributes to genetic mutations in lung cells, similar to the mutations seen in smokers. By analyzing lung tumors from 871 never-smokers across various regions with differing pollution levels, scientists identified specific DNA mutational signatures indicative of past environmental exposures. Higher pollution exposure correlated with an increased number of mutations, especially those promoting cancer growth, and was associated with signs of accelerated cellular aging.

Interestingly, the study found that secondhand smoke had a relatively minor genetic impact compared to air pollution. While it did cause some telomere shortening (a marker of aging), it did not lead to significant mutational signatures linked to cancer. In contrast, exposure to aristolochic acid, a carcinogen present in certain herbal medicines, was strongly associated with lung cancer cases in Taiwan. This raises public health concerns about the potential carcinogenic risks of traditional herbal remedies.

The research also uncovered a novel mutational signature prevalent in many never-smoker lung cancers without a known environmental cause. The origin of this new pattern remains unknown, warranting further investigation.

Overall, these findings emphasize the importance of environmental factors in lung cancer development among never-smokers and call for increased awareness and regulation of air quality and traditional herbal medicines. Future research aims to further understand other environmental risks, including radon and asbestos exposure, and explore the effects of emerging substances like e-cigarettes and marijuana.

For more detailed insights, see the original study: Maria Teresa Landi, The mutagenic forces shaping the genomes of lung cancer in never-smokers, Nature (2025), DOI: 10.1038/s41586-025-09219-0. Source: https://medicalxpress.com/news/2025-07-particulate-air-pollution-linked-mutations.html