A recent study has revealed measurable changes in the blood of people exposed to air pollution, preceding their lung cancer diagnosis by several years.
The results provide promising evidence that could help shape future research, detection, and prevention strategies for this malignant disease.
Although air pollution is already known as a major environmental cause of lung cancer, the precise biological mechanisms linking pollution exposure to the disease have remained unclear. This study, led by researchers from the American Cancer Society and Emory University and published in the journal Nature Communications, sought to fill this gap by analyzing blood samples from more than 1,357 healthy individuals and detecting changes in small molecules called metabolites that were associated with long-term exposure to air pollution. These changes included disruptions in vital processes such as inflammation, oxidative stress, detoxification, and energy metabolism, all of which are known to increase the risk of cancer.
These findings are of particular importance because, although tobacco smoking remains the leading risk factor for lung cancer, a large proportion of cases are diagnosed in non-smokers, indicating that other risk factors, such as air pollution, play an important role, but are not currently adequately included in screening and early detection strategies.
The researchers believe that the biological changes that have been observed may pave the way for the development of blood biomarkers that help identify people at higher risk and strengthen the evidence needed to include air pollution in future prevention and screening strategies.
In her commentary, Dr. Ying Wang, chief scientist at the American Cancer Society and co-author of the study, explained that outdoor air pollution is classified as a carcinogen, and that the link between it and lung cancer is sometimes stronger among non-smokers, indicating an important biological mechanism that is still not understood. This study is a first step towards understanding those mechanisms by monitoring changes in the body years before diagnosis.
Dr. Donghai Liang, an associate professor of environmental health at Emory University and co-author, added that identifying these changes in blood metabolites associated with air pollution gives them a clearer picture of the biological processes that link pollution to cancer, and with further verification, may one day help identify people at high risk and revise screening criteria to include environmental factors.
