Bladder cancer may be linked to the body’s response to a common virus that infects nearly everyone during childhood, according to new research led by scientists at the University of York.
The study focused on BK virus, which can establish a lifelong, dormant infection in the body, most often in the kidneys. The virus can reactivate when the immune system weakens, such as with age.
Researchers examined BK virus infections in the urothelium, the tissue lining the bladder and upper urinary tract. Using advanced DNA sequencing techniques, they tracked patterns of DNA damage caused by the virus in laboratory-grown human tissue. These patterns acted like “fingerprints,” helping the team identify what triggered the damage.
They found that antiviral enzymes, deployed by urothelial cells to fight BK virus, can inadvertently damage the cells’ own DNA. Over weeks and months, this “friendly fire” created DNA damage patterns similar to those seen in bladder cancer.
Unexpectedly, the DNA damage was also observed in neighboring, uninfected cells. This “bystander effect” may explain why bladder cancers rarely contain the virus itself years after infection.
Lead author Dr. Simon Baker of York’s Department of Biology said the findings could open new avenues for prevention. “Just as HPV vaccines help prevent cervical cancer, we may eventually be able to treat BK virus early and prevent bladder cancer from developing,” he said.
Bladder cancer remains relatively rare, with around 10,000 new cases in the UK annually, mostly in adults over 60. However, kidney transplant recipients face a threefold higher risk, as BK virus can reactivate and damage urinary tract cells.
Dr. Baker noted, “We know BK virus can cause bladder cancer in transplant patients, but the virus is absent in most other bladder cancers. This led us to investigate whether BK could trigger cancer indirectly, without being present in tumor cells.”
The research team plans to pursue clinical studies to confirm a causal link and explore how BK virus interacts with other risk factors, such as smoking.
“This research represents a major shift in our understanding,” Dr. Baker said. “While lifestyle factors like smoking remain important, these findings suggest we could prevent bladder cancer by stopping early virus-triggered damage.”
Dr. David Crosby, chief research officer at Kidney Research UK, said, “This work shows how research funding can drive discoveries with broad impact. Tackling BK virus early could one day prevent bladder cancer, protecting both kidney health and overall long-term wellbeing.”
Professor Stephen Leveson of York Against Cancer added, “Bladder cancer research has historically been underfunded, especially in Yorkshire where rates are higher. This study offers valuable insights into how BK virus contributes to cancer development and may guide future diagnosis and treatment strategies.”
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