The median values for circulating CD34-positive cell counts were 24.8/μl (1.1–1892.6, n = 63) at the time of myelofibrosis diagnosis, 82.7/μl (0.34–230.0, n = 8) for disease progression, 25.2/μl (0.2–2032.7, n = 57) for stable disease, 35.5/μl (0.5–672.4, n = 27) for clinical improvement and 2.8 (0.1–73.5, n = 23) for partial or complete response. Here, CD34 is linked to myelofibrosis.