Does XMRV cause prostate cancer? The controversy continues
Posted Nov 21 2010 12:00am
Regular readers of these columns will be aware that a while ago it was first suggested that a virus known as xenotropic murine leukemia virus-related virus or XMRV was associated with at least some cases of prostate cancer. Since that original publication, there has been a significant stream of articles that seem to either confirm the original finding or suggest that there is no association between XMRV and risk for prostate cancer.
Proving a negative is always difficult, so it is going to be hard to prove that there is no association between XMRV and prostate cancer, but some recent data from specialists in retrovirus-induced infectious diseases appear to offer a strong suggestion that the possibility of a connection between XMRV and prostate cancer is at best not very likely.
Aloia et al. used a series of highly sensitive methods in attempts to identify the presence of XMRV in a set of nearly 800 prostate cancer tissue samples. The methods they used included:
We don’t intend to get into the details of the techniques. Suffice it to say that these are highly sophisticated methods capable of detecting XMRV in a single infected cell even in the presence of up to 10,000 uninfected cells.
According to Aloia et al., they were unable to find any evidence of XMRV infection in any of these nearly 800 prostate cancer tissues in their experiments.
They conclude that, “It is possible that XMRV is not actually circulating in the human population; even if it is, the data do not seem to support a causal role for this virus in [prostate cancer].”
As attentive readers may have noted, it has also been suggested that XMRV may be associated with chronic fatigue syndrome (CFS), but if XMRV “is not actually circulating in the human population,” then it wouldn’t be possible for XMRV to be the cause of CFS either.
It is rapidly becoming important that we clarify whether XMRV really is a virus that can be commonly found in man and whether it is associated with any form of subsequent disease including prostate cancer. The American Association of Blood Banks is already recommending that patients with a clinical diagnosis of CFS (and certain other conditions) be asked to avoid donating blood. As yet this direction has not been given to men with a history of prostate cancer.