I was surprised when I heard Dr. Peterson say that XMRV in prostate cancer is similar but not identical to XMRV in CFS. He says it early on in this video of his first presentation: http://www.youtube.com/watch?v=053fYeLblmo&feature=channel I think this is very significant for us. I also had no idea there were many mouse retroviruses. How weird. Dr. Peterson then goes on to say in the 2nd video that white blood cells from the XMRV positive patients were able to infect the cell line for prostate cancer and controls were not able to: http://www.youtube.com/watch?v=U-kmo0w-9Vs&feature=channel What do you all think about this?