Essential thrombocythemia: new advances in an old disease

Author(s): Clodagh Keohane , Claire Harrison

Essential thrombocythemia (ET), a Philadelphia-negative myeloproliferative neoplasm, is characterized by thrombocytosis, megakaryocytic hyperplasia and vascular complications. It has been recognized as a distinct clinical entity since the 1930s but our understanding of its pathogenesis and available therapies remained static for many years. The last decade has witnessed a proliferation of research interest and clinical trials both for ET and related diseases. Much of this work stemmed from the seminal discovery of the JAK2V617F mutation in 2005, which has germinated a far greater understanding of the genetic and epigenetic complexity of ET. Targeted therapies are already in clinical use and newer agents are in clinical trials. This review focuses on the recent advances in therapy as well as diagnosis, pathogenesis and risk stratification. However, there are still unanswered questions about this disease, including the management of low- and intermediate-risk patients as well as the factors that predict disease progression.