Myeloproliferative Neoplasms

Hematopoietic pluripotent stem cells have self-renewal capability and give rise to either myeloid or the lymphoid lineage which further differentiates into various mature blood cells such as red blood cells (RBC), lymphocytes, granulocytes, megakaryocytes, and macrophages. The hematopoietic process is determined by the bone marrow environment, growth factors, and transcription factors. The abnormal proliferation of one or more terminal myeloid cell lines in the peripheral blood gives rise to a heterogeneous group of disorders called myeloproliferative neoplasms. In 1951, William Dameshek coined the term which are now reformed to myeloproliferative neoplasms (MPNs) by the World Health Organization (WHO). Chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are four classic types of myeloproliferative neoplasms. WHO classification also included chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia (CEL), and MPN, unclassifiable. Out of the classic types of MPNs, CML is positive, but PV, ET, and PMF are negative. Besides, the fourth edition of WHO classification for myeloid and acute leukemia was revised in 2016 due to recent advances in hematology with the identification of molecular markers and prognostic markers, giving a better understanding of the molecular pathogenesis and genetics of the hematological malignancies.