Breast cancer survivors who have been in remission for years or even decades may still need to be cautious about respiratory infections, according to new research. Some common viruses have been found to re-awaken dormant breast cancer cells within the lungs, posing a potential risk for cancer relapse.
Molecular geneticist James DeGregori from the University of Colorado likens dormant cancer cells to embers in an abandoned campfire, with respiratory viruses acting as a strong wind that reignites the flames. This discovery emerged following the COVID-19 pandemic, where a noticeable increase in cancer cases was observed.
Studies conducted on patients in remission for cancer who tested positive for SARS-CoV-2 showed a twofold increase in cancer-related death. Epidemiologist Roel Vermeulen from Utrecht University in Sweden described this increased risk as significant and almost unheard of in epidemiology for cancer.
Further analysis on a breast cancer database in the United States revealed that a previous SARS-CoV-2 infection was associated with a greater than 40 percent increased risk of metastatic breast cancer in the lungs. Studies in mice also showed that influenza and SARS-CoV-2 infections triggered dormant breast cancer cells to proliferate rapidly, leading to metastatic lesions.
Scientists have long suspected that certain viruses, like Epstein-Barr Virus (EBV), have the potential to trigger cancer. The human papillomavirus (HPV) is already known to cause cervical cancer. Research has been ongoing to find a virus that triggers breast cancer, with high-risk viruses detected in breast cancer tissue samples.
The immune system’s response to viruses may play a role in cancer spread. Viral respiratory infections like the flu and COVID-19 can cause inflammation, potentially waking up dormant cancer cells. In mouse experiments, influenza A virus and the coronavirus reawakened dormant cancer cells in the lungs by triggering an increase in inflammatory cytokines.
The findings suggest that the immune response to viruses creates an environment for cancer proliferation. It is crucial to protect breast cancer survivors who may face an increased risk of relapse if they contract a respiratory virus. Further research is needed to determine if vaccination against influenza or COVID-19 can help mitigate this risk.
The study highlighting these findings was published in Nature, emphasizing the importance of understanding the potential risks associated with respiratory infections for cancer survivors.
