. >> mcfarland: ronald evans is a lifelong musician and makes his home in gainesville, georgia, a little an hour's drive north of atlanta. ronald is 72. ronald's myelofibrosis came about as a result of having another disorder associated with the jak2 gene called polycythemia vera. >> and for years, i produced too many blood cells, too many red blood cells. in about 1992, the--the bone marrow started hardening, or scarred, as my doctor said. and so the bone marrow then didn't produce enough blood cells. and for the next eight years or so, the spleen took over and helped me produce my red blood cells. and in 1998, we had to have the spleen removed because it had grown so large. and so the liver did take over. and for about eight or ten years, the liver began to grow. >> mcfarland: for the most part, it takes t myelofibrosis, and there is an assortment of measurements that can be used to do that from a physical exam to imaging studies of the bone, spleen, and liver and to blood tests and finally to the most precise diagnostic procedure, an examination of the bone marrow. >> i'm just going t