Which chronic myeloproliferative disorder is NOT associated with the JAK2(V617F) mutation?

Chronic myelogenous leukemia (CML) is specifically characterized by the presence of the Philadelphia chromosome, which results from a translocation between chromosomes 9 and 22 leading to the formation of the BCR-ABL fusion protein. This mutation drives the pathogenesis of CML, resulting in uncontrolled proliferation of myeloid cells. The hallmark of CML is not the JAK2(V617F) mutation, which is predominantly associated with other myeloproliferative neoplasms.

In contrast, essential thrombocythemia, idiopathic myelofibrosis, and polycythemia vera are all closely linked to the JAK2(V617F) mutation, which plays a crucial role in their development and progression. This mutation affects the signaling pathways that regulate hematopoiesis, leading to increased proliferation of blood cells in these disorders. Therefore, the absence of the JAK2(V617F) mutation in chronic myelogenous leukemia distinguishes it from the other three conditions.