Besides the three classical mutations in JAK2, CALR, and MPL that are commonly referred to as MPN driver mutations, non-driver mutations in the genes known from MDS and AML are also detected in polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF)15,17,18. This evidence concerns the gene JAK2 and acquired polycythemia vera.