Effect of IFN on PV stem cells. (A) Simplified scheme of different stem cell compartments in polycythemia vera. Dormant normal stem cells do not contribute to productive hematopoiesis and coexist alongside clonal stem cells with and without JAK2V617F somatic mutation(s). (B) It remains to be determined whether interferon preferentially stimulates proliferation of dormant normal hematopoietic cells, clonal JAK2V617F⁻, or JAK2V617F⁺ subclone stem cells. Professional illustration by Alice Y. Chen.