In polycythaemia vera(PV)patients with the NFE2 gene mutation, the proportion of those classified as high-risk is notably higher in both the IWG-PV and mutation-enhanced international prognostic systems for PV(MIPSS-PV)(66.7% vs 25.3% for IWG-PV, P=0.033; 22.2% vs 2.0% for MIPSS-PV, P=0.013). This evidence concerns the gene NFE2 and acquired polycythemia vera.