Levels of JAK2 V617F in treated and control PV cases. (A) Comparison of %V617F in control, mutation-positive PV cases who were either treated or not treated with imatinib or rIFNα. (B) Comparison of %V617F in control PV cases and patients who showed CR, PR, or NR following therapy with imatinib or rIFNα. Vertical lines indicate the range of results; boxes, the interquartile range; and thick horizontal lines, median values. (C) Changes in %V617F on imatinib therapy. The %V617F was measured before starting imatinib and at various times while on therapy for 7 patients who showed no response (NR) or a partial response (PR), and 2 patients who showed a complete response (CR). (D) Comparison of %V617F level in peripheral blood and bone marrow from 11 control PV cases.