Hello my fellow PV club members. I would like to add another theory to the mysterious cause of PV. Toxic material exposure. I retired from the US Army after 30 years of service all over the world. I was assigned to Fort Detrick, MD, home of the U.S. Army Medical Research Institute for Infectious Diseases where there was an anthrax spill which contaminated an entire building which remains vacant to this day. I was in Iraq and in Afghanistan and exposed to Ionizing radiation exposure, Burn pits, Sand, Dust, Particulates, Oil well fires, Sulfur fires, and Pesticides. I currently have a VA disability claim pending to get my PV as "service connected" so my wife will receive beneifts when I die. Who is to say what the cause of PV is? I go to a fantastic oncology center in Kentucky where I see other cancer patients experiencing terrible effects of their cancers. My PV has little effect on me and I am blessed I have PV which I call the diet coke of cancers. I remain active, go to my gymnasium 3 times a week, and recently came back from a Disney cruise with my grand children. Let us live every day as if there is no tomorrow. Enjoy every mintue of this glorius time on earth. From the Heartland of America where I walk barefoot in the cool Kentucky Bluegrass. I wish you all the best!