[Application of genetic data to clinical practice of MPN]

After the discovery of the JAK2V617F mutation in 2005, followed by the discovery of the MPL and JAK2 exon 12 mutations, and the CALR mutation in 2013, the majority of patients with Philadelphia negative myeloproliferative neoplasms (MPN) have been shown to display one of these somatic mutations. In regards to the pathogenesis of MPN, the CALR mutation has been shown to activate the JAK2 downstream cascade. However, the mechanism has yet to be elucidated. Nevertheless, these investigations have changed our understanding of MPN, especially in terms of diagnosis and treatment. Reports on the clinical effects of the different somatic mutations have revealed that MPN patients with CALR-mutated ET are less likely to have thrombosis, and that PMF patients with the CALR mutation have better overall survival. Hereafter, evaluations of the status of these gene mutations are necessary for the diagnosis of MPN, and it is important to consider how to put these genetic data to the best possible practical use.