Classification of Myeloproliferative Neoplasms and Prognostic Factors

Abstract

Myeloproliferative neoplasms (MPNs) are currently diagnosed according to the World Health Organization (WHO) criteria. Molecular profiling should include the analysis of JAK2 V617F (first, exon 12 only in V617F-negative polycythemia vera [PV]) and MPL mutations (in V617F-negative essential thrombocythemia [ET] and myelofibrosis [MF]). For patients with PV and ET, the risk stratification of low- and high-risk disease requires only two parameters: older than age 60 and prior history of thrombosis. Additionally, it might be important to monitor leukocyte count and know the mutational profile. Survival of patients with MF is defined by the International Prognostic Scoring System (IPSS) model at diagnosis and the Dynamic IPSS (DIPSS) anytime during the course of the disease. The IPSS and the DIPSS are based on patient age older than age 65, presence of constitutional symptoms, hemoglobin level less than 10 g/dL, leukocyte count greater than 25 × 10(9)/L, and circulating blast cells 1% or greater. The DIPSS-plus adds critical prognostic information and suggests also considering cytogenetic categories, platelet count, and red blood cell transfusion need.