Air pollution a major factor in lung cancer among never-smokers: study

Never-smokers exposed to high levels of fine particulate air pollution have a significantly greater risk of developing lung cancer, according to a study published July 2 in Nature by the University of California San Diego and the National Cancer Institute. The study found cancer-driving genetic mutations and signs of accelerated cellular aging in lung tumors from never-smokers across 28 global regions, prompting renewed focus on overlooked environmental risks.

Researchers analyzed tumor genomes from 871 never-smokers using whole-genome sequencing. They found a strong dose-response link between air pollution levels and mutation frequency, including a 3.9-fold increase in tobacco-related mutation signatures and a 76% rise in aging-related patterns. Mutations were especially common in the TP53 gene, a known driver of lung cancer. In contrast, tumors from secondhand smoke exposure showed only minor changes. The study also detected a unique mutational signature associated with aristolochic acid, a carcinogen found in certain traditional herbal medicines, among patients in Taiwan.

The study’s findings reinforce those of the 2023 Female Asian Non-Smoker (FANS) study, led by the University of California Davis Comprehensive Cancer Center, which found that 57% of Asian American women diagnosed with lung cancer had never smoked. Urban air pollution was identified as one of the major exposures of concern, alongside cooking fumes and secondhand smoke.

With nearly one in four lung cancer cases now occurring in people who have never smoked, researchers are calling for updated screening guidelines that consider environmental and demographic risk factors. Bryant Lin, co-founder of Stanford’s Center for Asian Health Research and Education, has also been raising awareness about the rise of lung cancer among never-smokers. Lin, who was diagnosed with stage IV lung cancer in 2021 despite never smoking, has become a leading voice advocating for expanded research, early detection and inclusive prevention strategies.