Iron parameters and JAK2 VAF as diagnostic markers for PV and ET

Results from a retrospective, single-center study comparing iron, erythropoietin (EPO), and mutational profiles in 260 patients with polycythemia vera (PV; n = 105) or essential thrombocythemia (ET; n = 155) were published in Annals of Hematology by González-Resina et al. The objectives of this study were to determine the diagnostic value of transferrin saturation index (TSI) vs ferritin and to establish the utility of JAK2 variant allele frequency (VAF) in discriminating between ET and PV.  

Key data: JAK2 mutations were observed in 74.2% of patients overall, most notably a V617F variant (99.5%). Patients with PV were more likely to have a JAK2 mutation compared with patients with ET (93.3% vs 61.3%; p < 0.001). Ferritin levels (p < 0.001), TSI values (p < 0.001), and EPO values (p < 0.001) were lower in patients with PV compared with patients with ET, while hemoglobin (Hb; p < 0.001) and hematocrit (Hct; p < 0.001) levels were higher in patients with PV compared with patients with ET. There was no significant difference in ferritin (p = 0.356), TSI (p = 0.345), or EPO (p = 0.134) between patients with PV vs ET who had JAK2 mutations. VAF was higher in patients with PV who had a JAK2 mutation compared with patients with ET who had a JAK2 mutation (p = 0.003). 

Key learning: Results suggest that TSI, EPO, and JAK2 VAF may serve as useful diagnostic markers to differentiate between PV and ET, supporting their inclusion in myeloproliferative neoplasm (MPN) diagnostic algorithms. Validation of these findings in prospective, multicenter studies with standardized assessment criteria is required.