In October 2009, a "retrovirus" XMRV was linked to chronic fatigue syndrome (ME/CFS). The report, published by researchers from the Whittemore Peterson Institute, the National Cancer Institute and the Cleveland Clinic, gave hope to the many sufferers of the disease.
Since then, over 30 studies have been conducted on the topic and not another single research study could link XMRV to ME/CFS.
In December 2011, the report was officially withdrawn by Science.
In October 2012, a ground-breaking 2006 study linking to XMRV to prostate cancer was also withdrawn, this time from the journal PLoS ONE.
What Is a Retrovirus? What is XMRV?
Retroviruses are RNA viruses that wrap themselves into the DNA of the host, replicating itself as part of the host's DNA.
According to the Centers for Disease Control and Prevention, XMRV is a specific strain of retrovirus called xenotropic murine leukemia virus-related virus, first identified in 2006 in samples from men with prostate cancer. These murine leukemia viruses cause cancer and other diseases in mice. Unfortunately, beyond that, not much is known about XMRV – its transmission is unknown and it is unclear if some people are more likely to have XMRV than others. Even the existence of XMRV in humans is still debated.
What is the controversy?
One of the major concerns is that particular strains of retroviruses can cause cancer. When originally linked to prostate cancer, this made sense; today, the CDC will only commit that the link between XMRV and prostate cancer or ME/CFS are "unknown." The hope, of course, was that the study of XMRV could provide insight into chronic fatigue syndrome and prostate cancer, where future investigations may also link XMRV to other cancers. Armed with new information, scientists could go about attacking cancers in new ways. Unfortunately, the air came out of the balloon when the reports were found to be incorrect.
That said, the retracted reports linking XMRV to prostate cancer and ME/CFS were supposedly the products of contamination. "Based on the genetic analysis, the scientists concluded that XMRV was not present in the original prostate rumor samples, but arose only after [the tumors] had been put into mice," stated a report issues by the National Cancer Institute.
The link has officially been debunked, though some unusual circumstances still surround XMRV's study: when the prostate cancer study was retracted, the journal did not contact its authors before pulling it, and in the case of ME/CFS, a series of strange events occurred, including the mysterious dismissal of a scientist who held out hope that ME/CFS and XMRV were linked.
Some still believe there are links between these mouse-borne cancer-causers and human diseases, but for now, it looks like the consensus is on contamination in previous studies. However, this virus was only discovered a mere six years ago, so the potential for new developments is always there.