A new study casts further doubt on the role of a retrovirus, XMRV, in human disease, adding weight to the possibility that earlier studies finding a link between the virus and cancer and chronic fatigue syndrome may have been wrong.
In the study, researchers from the National Cancer Institute and Johns Hopkins Medicine report being unable to find any evidence of the retrovirus in nearly 800 prostate cancer samples.
"It is possible that XMRV is not actually circulating in the human population," the team wrote in its paper published by the journal Cancer Research last week.
Scientists have been wrestling with XMRV since 2006, when a research team reported finding a link between XMRV and prostate cancer. The finding, if confirmed, would have massive implications for the detection, prevention and treatment of the cancer.
Then, almost exactly one year ago, a team of researchers led by the Whittemore Peterson Institute for Neuro-Immune Disease reported a new link — this time between chronic fatigue syndrome and XMRV. That news also caused enormous waves. Patients diagnosed with the syndrome expressed excitement that a potential cause of their illness had finally been found and that effective therapies for the frustrating disorder might be on the horizon.
A commercial lab began selling commercial lab tests to detect XMRV. Some chronic fatigue syndrome patients started taking potent antiretroviral drugs usually used to treat HIV.
But in both prostate cancer and chronic fatigue syndrome, independent teams of researchers have had trouble replicating the findings. No team has published a confirmation of the link between XMRV and CFS. Negative studies have piled up, and there are doubts about the original findings.
This latest study used two techniques -- polymerase chain reaction and immunohistochemistry – to look for evidence of XMRV in nearly 800 samples from prostate tumors. The scientists found no signs of XMRV.
"Over the years, many claims associating viruses with diseases have turned out to be mistaken," they wrote. "It is still possible that XMRV will fall into this category."
Meanwhile, patients in the chronic fatigue syndrome community are clamoring for clinical trials of antiretroviral drugs. Patients in England are organizing a protest Nov. 1 in London. Organizers are encouraging protesters to bring wheelchairs, signs and to make effigies of people they consider villains in the world of their disorder.
—Trine Tsouderos / Chicago Tribune