Regarding BCR-ABL1??negative MPN patients this case report provides strong support for a role of JAK2 activation in the oncogenesis and suggests a possible diagnostic and therapeutic target that should be investigated.     ///     BCR-ABL1 negative myeloproliferative neoplasms (MPNs) are known to contain alterations of the tyrosine kinase JAK2 (located on 9p24) that result in constitutive activation of the encoded protein. 