JAK2 and acquired polycythemia vera: We found a differential expression pattern between the bone marrow of controls (median of 20% positive granulocytes, range 2-99%, SD 39.05%) and PV (median of 95% positive granulocytes, range 65-99%, SD 16.72%), ET JAK2 V617F (median of 67% positive granulocytes, range 5-99%, SD 36.04%), and ET JAK2 wild-type (median of 98% positive granulocytes, range 3-98%, SD 38.31%).