BioProject

Polycythemia vera (PV) and essential thrombocythemia (ET) are Philadelphia-negative myeloproliferative neoplasms (MPNs) characterized by erythrocytosis and thrombocytosis, respectively. More...

Polycythemia vera (PV) and essential thrombocythemia (ET) are Philadelphia-negative myeloproliferative neoplasms (MPNs) characterized by erythrocytosis and thrombocytosis, respectively. Approximately 95% of PV and 50–70% of ET patients harbour the V617F mutation in the exon 14 of JAK2 gene, while about 20-30% of ET patients carry CALRins5 or CALRdel52 mutations. These ET CARL-mutated subjects show higher platelet count and lower thrombotic risk compared to JAK2-mutated patients. Here we showed that CALR-mutated and JAK2V617F-positive CD34+ cells have different gene and miRNA expression profiles. Indeed, we highlighted several pathways differentially activated between JAK2V617F- and CALR-mutated progenitors, i.e. mTOR, MAPK/PI3K and MYC pathways. Furthermore, we unveiled that the expression of several genes involved in DNA repair, chromatin remodelling, splicing and chromatid cohesion are decreased in CALR-mutated cells. According to the low risk of thrombosis in CALR-mutated patients, we also found the down-regulation of several genes involved in thrombin signalling and platelet activation. As a whole, these data support the model in which CALR-mutated ET could be considered as a distinct disease entity from JAK2V617F-positive MPNs and may provide the molecular basis supporting the different clinical features of these patients. Overall design: Gene expression profile (GEP) and miRNA expression profile (miEP) were performed starting from the same total RNA of CD34+ cells from 50 MPN patients (1 replicate for each sample). In particular, GEP and miEP were performed on 26 PV and 24 ET (n=17 JAK2V617F-positive ET, n=7 CALR-mutated ET). In addition, 15 bone marrow (BM) samples collected from normal donors were included in the study (GSE53482). These re-analyzed samples have been included in this series for completeness. This series includes only the miEP samples. Less...