Mutation status defines subtypes of essential thrombocythemia and relation to polycythemia vera in Iraqi Patients

Abstract

Background: Polycythemia vera (PV) and essential thrombocythemia (ET) are a part of the BCR-ABL1-negative myeloproliferative neoplasms (MPNs) that harbor mutation in Janus kinase 2 (JAK2), CALR, or MPL gene. Objectives: The objective of this study was to investigate the impact of JAK2 and CALR mutations on the clinical course and hematological phenotype of ET patients and to evaluate the biological and clinical features of ET and PV sharing the same type of mutation in JAK2V617F. Materials and Methods: This was a cross-sectional study that included 94 patients diagnosed with MPN, of them 47 had PV and 47 had ET. JAK2V617F mutation was assessed using either allele-specific PCR or JAK-2 quantitative real-time PCR kit. JAK2-negative patients were further assessed for the existence of CALR mutations using SNP biotechnology MPN screening kit. Results: JAK2 mutation was identified in 29 ET patients, whereas CALR mutations were confirmed in 18 patients. JAK2-mutated ET patients were significantly older than those with CALR mutations. Seventy-six were reported to have a mutation in JAKV617F, of them 47 were diagnosed as PV and 29 as ET. JAK2V617F-mutated PV patients had significantly higher levels of hemoglobin, hematocrit, and WBC than JAK2-mutated ET patients. On the other hand, JAK2-mutated PV patients exhibited lower platelet count than ET harboring the same mutation. Conclusion: JAK2-mutated ET represents a distinct clinical entity that has a hematological and clinical phenotype ranging between JAK2-mutated PV and CALR-mutated ET. The analysis of the mutational status is essential in discriminating subtypes of MPN and confirming the diagnosis in ET and PV patients.