Prostate cancer caused by a virus?
Ah! It always feels good to read something that supports a theory- particularly when it comes to learning something about cancer- such a ubiquitous and noxious disease. In the recent issue of The Scientist, there is an article suggesting the idea of a viral cause for prostate cancer. Viral origins for cancer is not a new concept, by any means, and some go so far as to believe that all cancer is due to viruses. Human papillomavirus is thought to cause some cervical cancers (and now we have Gardasil and GSK’s new Cervarix® to hopefully reduce that risk) so why should it come as a shock for a virus could cause prostate cancer?
I find this article particularly interesting because my master’s thesis examined a large dataset (SEER registry cases) of prostate cancer cases and controls for factors which interacted with an increased 3-fold risk of having a first degree relative with prostate cancer. While the results of this study did not find an association between an increased number of sexual partners and prostate cancer directly, it did find a highly significant association and interaction between a high number of lifetime sexual partners (20+) and men who had one first degree relative with prostate cancer (RR: 4.5, 95%C.I.2.4-8.5). Unfortunately, due to political reasons (a senior person at NCI wanted to publish his own analysis on family history risk), I was not permitted to publish this finding. I have always suspected that having a large number of sexual partners in a lifetime would be associated with increased risk of sexually transmitted organisms, which could easily be a virus similar to HPV. Since many of these viruses ubiquitously infect the majority of people are exposed to them, the rate limiting factor for how soon a man develops prostate cancer (and it is thought that most all men will develop this cancer if they live long enough) may depend on his personal genetic makeup and resistance to viral infection and/or viral mutation of somatic cells in the prostate.
So what do you think? Would love to hear any opinions on this!
