New research from the UK has uncovered a significant link between a common childhood virus and an increased risk of developing bladder cancer later in life. The findings, described as a 'major shift in thinking', point to the BK virus as a potential trigger for the disease.
How a Dormant Virus Can Cause Lasting Damage
The study, led by Dr Simon Baker from the University of York, focused on the BK virus. This pathogen is typically contracted in childhood, causing mild, cold-like symptoms before becoming dormant in the kidneys, bladder, and ureters. In most people with healthy immune systems, it remains inactive and harmless.
However, the research team discovered that the virus can specifically trigger DNA damage in the tissue lining the urinary tract, known as the urothelium. Crucially, this damage is caused by the body's own defensive response to the infection. The damage occurs not just in infected cells, but also in surrounding 'bystander cells', a mechanism that may explain why tumours diagnosed years later often show no trace of the virus itself.
A Critical Risk for Kidney Transplant Patients
The findings have profound implications for kidney transplant recipients, a group known to be at higher risk of both BK virus reactivation and bladder cancer. Patients must take powerful immunosuppressant drugs to prevent organ rejection, which can allow the dormant virus to reactivate.
It is estimated that around six per cent of kidney transplant patients develop BK virus, which can attack kidney cells and reduce organ function. This group is over three times more likely to develop bladder cancer than the general population. Dr Baker stated the research finally explains the suspected link: 'We can now see how BK virus may contribute to bladder cancer, in transplant recipients and the general population.'
The human impact is starkly illustrated by the experience of Tim Tavender from Southampton. He developed BK virus after a transplant in 2015 and was diagnosed with bladder cancer six years later after noticing blood in his urine. The 51-year-old underwent a 13-hour surgery to remove his bladder. 'It was a terrifying experience,' he said, expressing hope that the new research could spare others.
New Pathways for Prevention and Hope
Published in the journal Science Advances, the study draws parallels with other virus-related cancers, such as cervical cancer caused by HPV. However, the mechanism in the bladder appears distinct, driven by tissue damage rather than viral DNA combining with human genetic material.
Dr David Crosby, chief research officer at Kidney Research UK, said: 'These findings move us closer to understanding why some people develop bladder cancer and show how tackling BK virus early could one day stop these cancers from developing at all.'
While smoking remains the leading cause of preventable bladder cancer in the UK, linked to around half of all cases, this research opens a vital new front. Bladder cancer is the 11th most common cancer nationally and the 7th most common in men, with about 80% of cases diagnosed in people over 65. Symptoms include blood in urine, frequent or painful urination, and unexplained weight loss.
The work provides strong motivation to develop prevention strategies, offering hope to patients and transplant recipients alike.
