Respiratory Infections Can Reactivate Dormant Breast Cancer Cells in the Lungs

Recent research conducted by teams at the University of Colorado Anschutz Medical Campus, Montefiore Einstein Comprehensive Cancer Center, and Utrecht University has uncovered compelling evidence that common respiratory viruses, including COVID-19 and influenza, may have the potential to reactivate dormant breast cancer cells that have spread to the lungs. This awakening of silent cancer cells can lead to the formation of new metastatic tumors, posing increased risks for cancer survivors.

Published in the journal Nature, the study utilized mouse models to simulate the metastatic process in humans. The researchers observed that respiratory infections triggered an immune response involving interleukin-6 (IL-6), a protein that promotes inflammation. Elevated levels of IL-6 appear to awaken dormant disseminated cancer cells (DCCs) in the lungs, which then rapidly expand into detectable metastatic lesions within days.

The findings are supported by epidemiological data showing that cancer patients who contracted COVID-19 experienced higher rates of cancer progression and death. Specifically, large population studies from the UK Biobank and the U.S. Flatiron Health database revealed that cancer survivors infected with respiratory viruses had nearly doubled risks of metastatic relapse, particularly soon after infection.

Dr. Julio Aguirre-Ghiso emphasized the importance of precautions for cancer survivors, recommending vaccinations and close discussions with healthcare providers. Meanwhile, the research team highlighted that IL-6 inhibitors or other immunotherapies could potentially prevent dormant cancer cells from reactivating during infections.

This multidisciplinary study underscores the long-term impact of respiratory viruses on cancer progression, especially in individuals in remission. It also points to potential therapeutic strategies to mitigate metastasis risk caused by common respiratory illnesses.