JAK2V617F positivity in patients with ET was associated with a clear increase in the odds of thrombosis [OR=1.83 (95% CI, 1.32-2.53), p<0.0001], and much higher odds of transformation to polycythemia vera [OR=7.67 (95% CI, 2.04-28.87), p=0.0009].
SOCS3 transcript levels were highest in patients with polycythemia vera and other JAK2 V617F positive myeloproliferative disorders, consistent with SOCS3 being a target gene of JAK2/STAT5 signaling.
JUNB was one of the genes upregulated in PV, and we confirmed, by quantitative real-time PCR, an overexpression of JUNB in hematopoietic cells of other JAK2 V617F PV patients.
CD239 was expressed in a constitutive fashion in PV-derived bone marrow cells and thus a pro-thrombotic function does not seem to be mediated by increased CD239 expression alone.
TET2 mutations were mainly observed (10 of 12) in patients with primary myelofibrosis or patients with polycythemia vera or essential thrombocythemia who secondarily evolved toward myelofibrosis or acute myeloid leukemia.
JAK2V617F is found in most patients with polycythemia vera, essential thrombocythemia, or primary myelofibrosis and is, therefore, useful as a clonal marker in those settings.
JAK2(V617F) is detected in other myeloproliferative neoplasms, does not appear to be the PV-initiating event, and its specific role in deregulated erythropoiesis in PV is incompletely understood.
AML1 mRNA expression was elevated in patients with PV, essential thrombocythemia, and primary myelofibrosis both in the presence and absence of JAK2(V617F).
JAK2 and MPL mutations appear to exert a phenotype-modifying effect and are distinctly associated with polycythemia vera, essential thrombocythemia and primary myelofibrosis; the corresponding mutational frequencies are approximately 99, 55 and 65% for JAK2 and 0, 3 and 10% for MPL mutations.
JAK2V617F mutation was found to be positive in 100% of polycythemia vera cases, 68.29% of essential thrombocythemia cases, and 55.28% of all MPD cases whereas negative in idiopathic erythrocytosis, reactive thrombocytosis, and other non-MPD cases such as acute chronic myeloid leukemias.
VEGF expression parallelled VEGFR-1 and resulted increased in Ph- MPNs (NCs: 0.08±0.04; ET: 0.13±0.06; PV: 0.29±0.2; PMF: 0.31±0.15) and higher in post-polycythaemic myelofibrosis and in the fibrotic stage of PMF than in the non-fibrotic phases of both diseases.
JAK2 inhibition in polycythemia vera (PV) and essential thrombocythemia (ET) for this class of agents appears promising to reduce myeloproliferations, symptoms, and perhaps prevent thrombohemorrhagic events.
LCN-2 mRNA showed a near 50-fold increase in expression, accompanied by down-regulation of SLC22A17, coinciding with increase in BCR-ABL transcripts, loss of JAK2-V617F and change of clinical phenotype from polycythaemia vera to chronic myeloid leukaemia.
CBL(mut) was not detected in polycythemia vera, primary myelofibrosis, essential thrombocythemia, or refractory anemia with ring sideroblasts and marked thrombocytosis.
Janus kinase-2 (JAK2) is mutated in a high proportion of patients with polycythemia vera and in a smaller number with essential thrombocythemia and primary myelofibrosis.
CALR mutations had a favorable impact on thrombosis-free survival (TFS) for ET patients, whereas the respective TFS outcomes were similarly poorer in JAK2-mutated ET and PV patients.