Returning cancer through a minor cold
A recent study published in the prestigious journal Nature on July 30, 2025, raises concerns about the potential impact of common respiratory infections like the flu and COVID-19 on cancer survivors. The study, led by James DeGregori at the University of Colorado Anschutz Medical Campus, suggests that these infections could reactivate dormant cancer cells, particularly in breast cancer survivors.
The study focused on genetically modified mice harboring dormant breast cancer cells. Infection with SARS-CoV-2 or influenza virus led to a significant increase in cancer cell proliferation in the lungs within two weeks, resulting in visible metastases. Interleukin-6 (IL-6), a protein the immune system uses to coordinate its response to infection, was identified as the critical inflammatory molecule activating these dormant cells.
Human epidemiological data support these findings. The UK Biobank study found that breast cancer survivors in remission for over five years who contracted COVID-19 had twice the risk of dying from cancer within a year post-infection. Similarly, the Flatiron Health registry data from over 36,000 breast cancer patients indicated those infected with COVID-19 had a 44–50% higher chance of developing lung metastases on follow-up.
While the direct human data focus mostly on HER2-positive breast cancer, the study suggests similar inflammatory mechanisms could apply to other cancers, though human evidence is currently limited. It's important to note that the mechanism is not the virus directly awakening cancer cells, but rather infection-induced inflammation triggering IL-6 release, which acts on dormant tumor cells.
Edwin Ostrin, a pulmonologist at MD Anderson Cancer Center in Texas, suggests that cancer patients should continue to be up to date on their current vaccinations to avoid respiratory illnesses. Julio A. Aguirre-Ghiso, the director of the Cancer Dormancy Institute, cautions that while many patients may not immediately develop symptomatic disease, inflammation could give dormant cells the leeway to multiply, severely increasing future risk.
Taken together, these results provide compelling evidence that respiratory illnesses like the flu and COVID-19 can indeed provoke dormant cancer cells to reactivate and promote metastatic disease, potentially explaining increases in cancer recurrence observed during the COVID-19 pandemic. However, these findings are relatively new, and while significant for breast cancer, especially HER2-positive subtypes, broader applicability to other cancers and clinical recommendations await further research.
- The study published in Nature raises concerns about the impact of respiratory infections like the flu and COVID-19 on individuals who have undergone medical-conditions such as cancer, with a focus on breast cancer survivors.
- The research implies that the environment of increased inflammation caused by respiratory illnesses may contribute to the reactivation of dormant cancer cells, which could lead to health issues like cancer recurrence.
- It's essential for individuals with a history of cancer, particularly breast cancer, to prioritize health-and-wellness through measures like staying up to date on vaccinations, to minimize the risk of respiratory infections.
- Further scientific exploration is required to establish whether similar inflammatory mechanisms, as observed in the study, could apply to other forms of cancer, offering insights into cancer progression and the development of effective treatment strategies.
