Sensitivity of individual MPN samples expressing JAK2(V617F), CALR(del52), and MPL(ex10mut) to PARPi. Lin⁻CD34⁺ primary cells from (A) healthy donors (n = 3) and from (B) JAK2(V617F)⁺, (C) CALR(del52)⁺, (D) MPL(ex10mut)⁺ MPN patients were incubated with olaparib (1.25, 2.5, 5.0 μM) or BMN673 (12.5, 25.0, 50.0 nM) for 96 hours in the presence of growth factors (100 ng/mL SCF; 10 ng/mL Flt3 ligand; 20 ng/mL IL-3, IL-6, granulocyte colony-stimulating factor, and GM-CSF; 12 U/mL Epo; 2.5 ng/mL thrombopoietin) followed by plating in methylcellulose. Colonies were counted after 7 to 10 days. Results represent the percentage of colonies in comparison with untreated control.