Covid and flu may activate breast cancer cells in lungs

Henriette Lamprecht Common respiratory infections caused by viruses may be able to activate sleeping breast cancer cells in the lungs and lead to metastatic disease, according to database and mouse studies. The study was published in the journal Nature.People with a history of breast cancer may have a higher risk of developing metastatic disease if they contract a respiratory infection caused by a virus.According to the researchers, people with a history of cancer may benefit from protecting themselves against respiratory infections. This includes receiving available vaccines, if possible, and wearing a face mask when in large crowds or enclosed spaces.Why do the study?During the first two years of the Covid pandemic, scientists noticed an increase in cancer deaths. This increase wasn’t due just to deaths from Covid or to delays in cancer screening and treatment. So many researchers began to wonder if there was a link between respiratory infections and the development of metastatic cancer in the lungs.About the studyThe researchers tested the link between respiratory infections and metastatic cancer in the lungs in a mouse model and analysing information from two databases. The information analysed was collected before Covid-19 vaccines were available.Detailed resultsMice with dormant breast cancer cells in their lungs were exposed to one of two respiratory viruses, either Covid-19 or the flu. In both cases, the infections triggered the cells to wake up and grow rapidly in just a few days, with metastatic tumours developing in 14 days.“Dormant cancer cells are like the embers left in an abandoned campfire, and respiratory viruses are like a strong wind that reignites the flames,” senior study author James DeGregori, PhD, said in a statement. DeGregori is the deputy director of the University of Colorado Cancer Centre.The researchers found that the cancer cells’ activation was caused by a protein called interleukin-6. Immune cells release this protein in response to infections or injuries. Medicines that target interleukin-6, which are available, might be able to prevent or slow the waking of cancer cells after an infection. But more research is needed to see if this approach works.In the two other parts of the study, the researchers analysed information from the UK Biobank and the US Flatiron Health databases, which both track diseases in people. They compared the mouse results to information about people with cancer who then had Covid-19.The Flatiron Health database includes information about women diagnosed with breast cancer from 280 cancer clinics in the United States. The researchers looked at data on women diagnosed with breast cancer in January 2011 or later. They wanted to know how many of the women developed lung metastases after testing positive for Covid-19 between the time they were diagnosed with breast cancer and August 2023. During about eight years of follow-up, women who had Covid-19 were about 50% more likely to be diagnosed with metastatic breast cancer in the lungs than women who didn’t have Covid-19.From the Biobank database, the researchers analysed information from 4 837 people who were diagnosed with early-stage cancer before 1 January 2015, five years before the start of the pandemic. People who tested positive for Covid-19 before December 2020 had almost double the risk of dying from cancer than people who tested negative.“Our findings indicate that individuals with a history of cancer may benefit from taking precautions against respiratory viruses, such as vaccination when available, and discussing any concerns with their healthcare providers,” study co-leader Julio Aguirre-Ghiso, PhD, said in a statement. Aguirre-Ghiso is director of the Montefiore Einstein Comprehensive Cancer Centre Cancer Dormancy Institute at the University of Colorado Anschutz Medical Campus. - Source: - breastcancer.org/Chia, S.B., Johnson, B.J., Hu, J. et al. Respiratory viral infections awaken metastatic breast cancer cells in the lungs. Nature (2025).

Covid and flu may activate breast cancer cells in lungs

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Republikein 2026-03-17

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Covid and flu may activate breast cancer cells in lungs

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Republikein 2026-03-17

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