Researchers from the University of Colorado Anschutz Medical Campus, Montefiore Einstein Comprehensive Cancer Center (MECCC), and Utrecht University have unveiled direct evidence that common respiratory viruses, including COVID-19 and influenza, can awaken dormant breast cancer cells in the lungs, setting the stage for new metastatic tumors. The groundbreaking findings, published today in the journal Nature, offer critical insights into the mechanisms behind cancer recurrence. This research highlights a significant connection between viral infections and the progression of metastatic disease.
The study utilized unique mouse models of metastatic breast cancer, which include dormant disseminated cancer cells (DCCs) in the lungs, closely mimicking the human condition. Exposure to SARS-CoV-2 or influenza virus triggered the awakening of these dormant DCCs, leading to a massive expansion of metastatic cells within days and the appearance of lesions within two weeks. This rapid progression underscores the potent impact of viral infections on cancer dormancy.
Supporting these experimental findings, human observational data from the U.S. Flatiron Health database and the UK Biobank revealed a substantial increase in lung metastatic progression among breast cancer patients who contracted SARS-CoV-2. Female breast cancer patients who experienced COVID-19 after their initial diagnosis exhibited a hazard ratio of 1.44 for subsequent diagnosis of metastatic breast cancer in the lungs. This indicates a 44% increased risk compared to those who did not contract the virus.
The researchers identified inflammation, particularly involving IL-6, as a key mediator in arousing these dormant cells. As Brian Roemmele stated in a tweet, > "Respiratory viruses can wake up breast cancer cells in the lungs." This discovery suggests that targeting IL-6 inhibitors or other immunotherapies could potentially prevent or lessen the resurgence of metastasis following viral infections. The findings have significant implications for understanding how infections could impact cancer recurrence risks and inform public and medical policy on mitigating these increased risks.