The Protective Virus: How a Common Cold Infection Could Stop Breast Cancer from Spreading
It sounds counterintuitive, but catching a common respiratory virus might actually help protect the body against one of the deadliest forms of cancer spread.
In a groundbreaking, early-stage study from Imperial College London and the Francis Crick Institute, researchers have discovered that previous exposure to respiratory syncytial virus (RSV)—a common virus that causes coughs and colds—appears to offer a protective effect against breast cancer metastasizing into the lungs.
The Threat of Lung Metastasis
When breast cancer is caught early, survival rates are generally high. However, the prognosis drastically changes if the cancer cells signal to new tissues and spread (metastasize) to other parts of the body.
“This is a big problem for breast cancer, which becomes much harder to treat if it spreads,” explains Dr. Ilaria Malanchi, a cancer biologist at the Francis Crick Institute.
The lungs are one of the most common target areas for breast cancer metastasis. The statistics are sobering:
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60% of Stage 4 breast cancer patients will develop a secondary tumor in their lungs.
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Once the cancer reaches the lungs, the five-year survival rate drops to just 30%.
Respiratory syncytial virus, the common cause of coughs and colds, offered a protective effect from breast cancer metastasising, researchers have discovered (stock photo)
The RSV Breakthrough: “Priming” the Lungs
Published in the prestigious scientific journal PNAS, the study focused on understanding how cancer cells manipulate healthy tissue environments to support tumor growth.
To test their theories, researchers introduced breast cancer cells into mice. The results were startling:
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Mice that had recently experienced an RSV infection had developed a heightened immune response specifically in their lungs.
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When exposed to breast cancer cells, these RSV-infected mice developed significantly fewer lung tumors compared to mice that had never caught the virus.
The researchers believe the prior viral infection essentially “primes” the immune system within the lungs, making the environment actively hostile to invading cancer cells.
Future Treatments: Mimicking the Virus
While these findings represent a major breakthrough in understanding how cancer spreads, experts emphasize that the actual RSV infection will never be used as a direct treatment. Catching a cold while battling cancer remains dangerous due to compromised immune systems.
Instead, the goal is to harness the mechanisms behind the protective effect.
Professor Cecilia Johansson, from Imperial College London’s National Heart and Lung Institute, outlined the next steps: “If we can find a way of making lungs more resistant to successful seeding of metastatic cancer cells, that’s encouraging. We hope a drug could be developed to mimic the effects we have observed.”
Before such a drug can be developed, the research team must conduct extensive human studies to confirm whether the protective effect observed in mice translates effectively to human patients. If successful, this knowledge could revolutionize preventative care for high-risk breast cancer patients.
