Proceedings of the International scientific and practical conference ―Science at the Frontier of Civilizations‖ (March 16-18, 2026) / Publisher website: www.naukainfo.com. – Helsinki, Finland, 2026. - 145 p.

6 Keywords: chronic myeloproliferative neoplasms, driver mutations, JAK2, CALR, MPL, non-driver mutations. Philadelphia-negative chronic myeloproliferative neoplasms (CMNPs) compromise a heterogeneous group of clonal myeloid stem cell diseases. which include polycythemia vera (PV) with a predominance of red blood cell overproduction, essential thrombocythemia (ET) with a predominance of platelet overproduction, and primary myelofibrosis (PMF) with excessive bone marrow scarring and fibrosis. The updated WHO classification also includes prefibrotic myelofibrosis (Pre-PMF), which distinguishes a group of patients with subtle phenotypic differences from ET and a higher rate of progression to myelofibrosis (MF) [1]. Despite the apparent differences, similarities in bone marrow morphology, the propensity for arterial and venous thrombus formation, and the propensity for secondary myelofibrotic or leukemic phase transformation clinically link these disorders. These phenotypic similarities were recognized long before the discovery of activating mutations in the JAK2, MPL, and CALR genes, and the demonstration of activated signaling through the Janus Kinase (JAK)/Signal Transducer and Activator (STAT) signaling pathway, which helped to further define these disorders. JAK2 V617F mutations are found in approximately 95% of patients with SP with JAK2 exon 12 mutations, present in virtually all remaining SP cases. JAK2 V617F mutation is present in approximately 50% of patients with ET and PMF with CALR and MPL mutations in the majority of the remaining patients. ―Triple-negative‖ patients constitute a small percentage of ET and PMF cases. Diagnostic criteria now place great emphasis on demonstrating the presence of these genetic alterations to confirm the suspected diagnosis [2]. Driver mutations are becoming increasingly important for predicting clinical outcomes, but accurate prognostic models require large, well-characterized cohorts. Studies suggest that this potential extends to myeloproliferative neoplasms, but larger cohorts and comprehensive gene sequencing are needed to obtain definitive answers [3].