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This article reports metabolic consequences of JAK2-mutant myeloproliferative neoplasms (MPNs) with a therapeutic translational impact: expression of mutant JAK2 induces abnormal metabolic activity of MPN cells, resulting in hypoglycemia, adipose tissue atrophy, and early mortality.

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From our data we conclude that the S100A8 and S100A9 granulocyte and plasma levels are increased in MPN patients, along with inflammation markers, depending on their JAK2V617F mutation allele burden. We also found that S100A8/9-mediated inhibition of the proliferation-related AKT and ERK1/2 signaling pathways can be decreased by CALR mutation-dependent TLR4 blocking and increased by RAGE inhibition in MPN.

The widely used current International Prognostic Scoring System (IPSS) for primary myelofibrosis (PMF) is based on clinical parameters. The objective of this study was to identify additional prognostic factors at the time of diagnosis, which could have an impact on the future treatment of patients with PMF. We conducted a study of 131 consecutive PMF patients with median follow-up of 44 months. Data on baseline demographics, clinical and laboratory parameters, IPSS, grade of bone marrow fibrosis (MF), as well as influence of concomitant comorbidities were analyzed in terms of survival. Comorbidity was assessed using the Adult Comorbidity Evaluation-27 (ACE-27) score and the hematopoietic cell transplantation comorbidity index. An improved prognostic model of survival was obtained by deploying the MF and ACE-27 to the IPSS. A multivariable regression analyses confirmed the statistical significance of IPSS (P<0.001, HR 3.754, 95% CI 2.130-6.615), MF>1 (P=0.001, HR 2.694, 95% CI 1.466-4.951) and ACE-27 (P<0.001, HR 4.141, 95% CI 2.322-7.386) in predicting the survival of patients with PMF. When the IPSS was modified with MF and ACE-27, the final prognostic model for overall survival was stratified as low (score 0-1), intermediate (score 2-3) and high risk (score 4-6) with median survival of not reached, 115 and 22 months, respectively (P<0.001). Our findings indicate that the combination of histological changes, comorbidity assessment and clinical parameters at the time of diagnosis allows better discrimination of patients in survival prognostic groups and helps to identify high-risk patients for a poor outcome.

The gene and protein expression profiles in myeloproliferative neoplasms (MPNs) may reveal gene and protein markers of a potential clinical relevance in diagnosis, treatment and prediction of response to therapy. Using cDNA microarray analysis of 25,100 unique genes, we studied the gene expression profile of CD34+ cells and granulocytes obtained from peripheral blood of subjects with essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF). The microarray analyses of the CD34+ cells and granulocytes were performed from 20 de novo MPN subjects: JAK2 positive ET, PV, PMF subjects, and JAK2 negative ET/PMF subjects. The granulocytes for proteomic studies were pooled in 4 groups: PV with JAK2 mutant allele burden above 80%, ET with JAK2 mutation, PMF with JAK2 mutation and ET/PMF with no JAK2 mutation. The number of differentially regulated genes was about two fold larger in CD34+ cells compared to granulocytes. Thirty-six genes (including RUNX1, TNFRSF19) were persistently highly expressed, while 42 genes (including FOXD4, PDE4A) were underexpressed both in CD34+ cells and granulocytes. Using proteomic studies, significant up-regulation was observed for MAPK and PI3K/AKT signaling regulators that control myeloid cell apoptosis and proliferation: RAC2, MNDA, S100A8/9, CORO1A, and GNAI2. When the status of the mTOR signaling pathway related genes was analyzed, PI3K/AKT regulators were preferentially up-regulated in CD34+ cells of MPNs, with down-regulated major components of the protein complex EIF4F. Molecular profiling of CD34+ cells and granulocytes of MPN determined gene expression patterns beyond their recognized function in disease pathogenesis that included dominant up-regulation of PI3K/AKT signaling.

The current widely accepted stratification defined by age and previous thrombosis in patients with essential thrombocythemia (ET) probably deserves deeper analysis. The aim of our study was to identify additional factors at the time of diagnosis, which have an impact on the thrombosis prediction. We conducted a study of 244 consecutive ET patients with median follow-up of 83 months. We analyzed the influence of age, gender, laboratory parameters, history of previous thrombosis, spleen size, JAK2 mutation as well as cardiovascular (CV) risk factors including arterial hypertension, diabetes, active tobacco use and hyperlipidemia in the terms of thrombosis. The most important predictors of thrombosis in multivariate Cox regression model were the presence of CV risk factors (p=0.004) and previous thrombosis (p=0.038). Accordingly, we assigned risk scores based on multivariable analysis-derived hazard ratios (HR) to the presence of 1 CV risk factor (HR=3.5; 1 point), >1 CV risk factors (HR=8.3; 2 points) and previous thrombosis (HR=2.0; 1 point). A final three-tiered prognostic model for thrombosis prediction was developed as low (score 0), intermediate (score 1 or 2) and high risk (score 3) (p<0.001). The hazard of thrombosis was 3.8% in low-risk group, 16.7% in the intermediate-risk group and 60% in the high-risk group (p<0.001). Patients with thrombotic complications during the follow-up had a significantly shorter survival (p=0.018). The new score based on CV risk factors and previous thrombotic events allows a better patient selection within prognostic-risk groups and improved identification of the high-risk patients for thrombosis.

It has been shown that angiogenesis and inflammation play an important role in development of most hematological malignancies including the myeloproliferative neoplasm (MPN). The aim of this study was to investigate and correlate the levels of key angiogenic molecules such as hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) in peripheral blood and bone marrow cells of MPN patients, along with JAK2V617F mutation allele burden and effects of therapy. HIF-1α and VEGF gene expression were decreased, while eNOS mRNA levels were increased in granulocytes of MPN patients. Furthermore, positively correlated and increased VEGF and eNOS protein levels were in negative correlation with HIF-1α levels in granulocytes of MPN patients. According to immunoblotting, the generally augmented angiogenic factors demonstrated JAK2V617F allele burden dependence only in granulocytes of PMF. The angiogenic factors were largely reduced after hydroxyurea therapy in granulocytes of MPN patients. Levels of eNOS protein expression were stimulated by Calreticulin mutations in granulocytes of essential thrombocythemia. Immunocytochemical analyses of CD34 cells showed a more pronounced enhancement of angiogenic factors than in granulocytes. Increased gene expression linked to the proinflammatory TGFβ and MAPK signaling pathways were detected in CD34 cells of MPN patients. In conclusion, the angiogenesis is increased in several cell types of MPN patients supported by the transcriptional activation of inflammation-related target genes, and is not limited to bone marrow stroma cells. It also appears that some of the benefit of hydroxyurea therapy of the MPN is mediated by effects on angiogenic factors. © 2016 Wiley Periodicals, Inc.