Kaplan-Meier analysis of overall survival in PMF patients. (A) The plot shows the overall survival in JAK2 wild-type (WT; n = 59) vs JAK2V617F mutated (V617F; n = 127) patients. (B) Overall survival of JAK2V617F mutated patients who had been categorized in quartiles according to the burden of mutated allele. P values are shown inside each box. Quartiles of V617F allele burden were as follows: first, 1% to 25%; second, greater than 25% to 50%; third, greater than 50% to 75%; fourth, greater than 75% to 100%.