In a prospective, observational study of 48 PV patients, IFNα was found to be more efficient in homozygous compared to heterozygous JAK2V617F hematopoietic stem cells (HSCs), followed by type 2 CALRmut HSCs and finally type 1 CALRmut HSCs [65]. The gene discussed is IFNA2; the disease is acquired polycythemia vera.