A new study led by scientists at the University of Oxford has revealed something surprising: a common virus carried by more than half of all adults may actually help skin cancer patients respond better to treatment.
The virus in question is cytomegalovirus, or CMV. Most people who have CMV don’t even know it—they don’t show symptoms, and the virus stays dormant in the body for life. But this quiet virus might be doing more behind the scenes than anyone expected.
Published in Nature Medicine, the study looked at 341 patients with melanoma, a serious and sometimes deadly form of skin cancer. The patients were being treated with immunotherapy, a powerful type of cancer treatment that helps the immune system attack cancer cells.
Although immunotherapy has changed the game for many melanoma patients, it doesn’t work for everyone. Some patients don’t respond well to treatment, while others suffer from serious side effects.
The Oxford researchers discovered that patients who had CMV in their system were more likely to respond well to a specific type of immunotherapy, known as PD-1 therapy.
This therapy works by blocking a protein that normally tells the immune system not to attack. When this protein is turned off, immune cells called T cells can recognize and fight cancer more effectively.
Interestingly, CMV-positive patients not only responded better to this PD-1 treatment, but they also experienced fewer severe side effects, especially conditions like colitis, which is painful inflammation in the colon. This means that knowing whether a patient has CMV before starting treatment could help doctors choose the best and safest therapy option for them.
What’s even more fascinating is that CMV might do more than just help with treatment. The study found that people with CMV developed metastatic melanoma—a form of the disease where the cancer spreads—later than those who didn’t have the virus.
For patients who had a certain genetic mutation (called BRAF) in their tumors, the protective effect of CMV seemed even stronger.
So, how does a harmless virus help fight cancer? The researchers believe it comes down to the immune system. CMV activates a special group of immune cells known as T cells. These are the same cells that immunotherapy tries to activate to fight cancer.
Because CMV forces the body to keep its immune system ready and alert, patients who already have CMV might have immune systems that are better prepared to respond to cancer treatment.
Professor Benjamin Fairfax, who led the study, explained that these findings could help doctors tailor treatments more precisely for each patient. If someone has had CMV in the past, they might benefit from different treatment choices compared to someone who hasn’t. This could lead to better results and fewer harmful side effects.
Even more importantly, this is the first time a virus that has nothing to do with cancer has been shown to affect how cancer develops and how treatments work. It raises new questions about how our immune systems are shaped by infections throughout our lives, and how that might change how we fight off diseases like cancer.
Although more research is needed to confirm these results in larger groups of patients and to understand the details of how CMV influences the immune system, the findings are exciting. They suggest that something as simple and common as a past viral infection could hold the key to improving cancer treatment and saving lives.
In summary, this study opens the door to new ways of personalizing cancer care. By taking a patient’s virus history into account, doctors may be able to choose better therapies, reduce harmful side effects, and possibly even prevent cancer from returning.
It’s a surprising example of how something that seems unrelated to cancer—like an old virus—might become a powerful tool in the fight against it.
If you care about skin health, please read studies about eating fish linked to higher risk of skin cancer, and Vitamin B3 could help prevent skin cancers.
For more information about health, please see recent studies about vegetable oil linked to spread of cancer, and results showing Vitamin D could help treat skin inflammation.
The research findings can be found in Nature Medicine.
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