Previously, groundbreaking investigations in Ph(-) CMPD detected an acquired mutation in the Janus kinase 2 (JAK2) in the majority of patients with polycythaemia vera (PV) and in up to 50% of patients with essential thrombocythaemia (ET) and chronic idiopathic myelofibrosis (CIMF).
Among haematologic neoplasm the mutation appears to be almost specific for Ph(-) CMPD but the different entities comprising polycythaemia vera (PV), essential thrombocythaemia and chronic idiopathic myelofibrosis (CIMF) are not discriminated by the mutation.
In a series of proven Ph- CMPDs classified according to World Health Organization criteria (n = 79), we detected the JAK2 mutation in 90% of polycythemia vera, 22% of cellular prefibrotic chronic idiopathic myelofibrosis, 60% of advanced chronic idiopathic myelofibrosis, and 27% of essential thrombocythemia.