4  Risk Stratification in PV

4.1 WBC count

• JAK2 allele burden directly correlates with WBC count

4.2 Higher JAK2 VAF

• Correlates with increased risk of venous thrombosis but NOT arterial

4.3 MIPSS-PV

4.4 Masked PV (mPV)

• Patients with mPV often present with a higher platelet count and a lower JAK2V617F allele burden at diagnosis compared to those with overt PV.

• mPV is associated with a poorer prognosis compared to overt PV. Studies have shown that mPV patients have higher rates of progression to myelofibrosis and acute leukemia, and inferior overall survival