The identification of an acquired mutation of JAK2 in patients with myeloproliferative disorders has raised questions about the relationship between mutationpositive and mutation-negative subtypes, timing of the JAK2 mutation, and molecular mechanisms of disease progression. Here we demonstrate that patients with V617F ؊ essential thrombocythemia do not commonly progress to become V617F ؉ . Consistent with the concept of distinct pathogenetic mechanisms, we show that patients with and without the JAK2 mutation have different patterns of cytogenetic abnormality, with virtually all patients carrying the 20q deletion or trisomy 9 being V617F ؉ . We also investigated the existence of a "pre-JAK2 " phase by comparing the proportion of clonally derived granulocytes, estimated from X-chromosome inactivation patterns (XCIPs), with the proportion of V617F ؉ granulocytes.

Summary The JAK2 V617F mutation is a frequent genetic event in the three classical Philadelphia‐chromosome negative chronic myeloproliferative disorders (Phneg.‐CMPD), polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF). Its occurrence varies in frequency in regards to phenotype. The mutation is found in the majority of patients with PV and about half of the patients with ET and IMF. These diseases are clonal stem cell disorders arising in an early stem cell progenitor. The level in the stem cell hierarchy on which the initiating genetic events and the JAK2 V617F mutation occurs is not known. The mutation has so far been detected in all cells of the myeloid lineage, whereas the potential clonal involvement of the lymphoid lineage is controversial. In this study, we detected the JAK2 V617F mutation by real‐time quantitative PCR (qPCR) in both B‐lymphocytes and T‐lymphocytes in a subgroup of patients with Phneg.‐CMPDs. These results demonstrate the origin of the JAK2 V617F positive disorders in an early stem cell with both lymphoid and myeloid differentiation potential.

The present study support the concept of the JAK2 V617F positive chronic myeloproliferative disorders as a biological continuum with phenotypic presentation in part influenced by JAK2 V617F mutational load.

In this large international cohort of patients treated with first-line immunochemotherapy, outcomes following SCNS remain poor. However, a moderate proportion of patients with isolated SCNS who received intensive therapies achieved durable remissions.

Purpose The general outlook for patients with diffuse large B-cell lymphoma (DLBCL) in first remission is important information for patients and for planning post-treatment follow-up. The purpose of this study was to evaluate the survival of patients with DLBCL in remission compared with a matched general population. Methods A total of 1,621 patients from the Danish Lymphoma Registry who were newly diagnosed with DLBCL between 2003 and 2011 were included in this study. All patients were ≥ 16 years of age at diagnosis and had achieved complete remission or complete remission unconfirmed after first-line rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or R-CHOP-like therapy. Results The 5-year post-treatment DLBCL survival was inferior to survival in the matched general population (78%; 95% CI, 76 to 80; v 87%; standardized mortality ratio, 1.75; P < .001). Excess mortality was present but reduced for patients achieving post-treatment event-free survival for 24 months (pEFS24; standardized mortality ratio, 1.27; P < .001). In age-stratified analyses, the survival of patients < 50 years of age was normalized to the general population after achieving pEFS24 ( P = .99). During the first 8 years after pEFS24, the average loss of lifetime was 0.31 mo/y (95% CI, 0.11 to 0.50 mo/y). Excess mortality diminished when analyzing death from lymphoma as competing event to death from other causes, suggesting that early and late relapse is responsible for increased mortality in patients with DLBCL. Conclusion Although this population-based study does not support complete normalization of survival for patients with DLBCL achieving pEFS24, the estimated loss of residual lifetime was low for patients in continuous remission 2 years after ending treatment. Therefore, pEFS24 is an appealing and relevant milestone for patient counseling and could be a surrogate end point in clinical trials.

The Philadelphia-negative chronic myeloproliferative neoplasms - essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) (MPNs) - have recently been shown to be associated with chronic inflammation, oxidative stress and accumulation of reactive oxygen species (ROS). Using whole blood transcriptional profiling, we report that several oxidative stress and anti-oxidative stress genes are significantly deregulated in MPNs. Among the twenty most up- and downregulated genes, ATOX1, DEFB122, GPX8, PRDX2, PRDX6, PTGS1, and SEPP1 were progressively upregulated from ET over PV to PMF, whereas AKR1B1, CYBA, SIRT2, TTN, and UCP2 were progressively downregulated in ET, PV and PMF (all FDR <0.05). The gene Nrf2, encoding the transcription factor nuclear factor erythroid 2-related factor 2 (NFE2L2 or Nrf2) was significantly downregulated in all MPNs. Nrf2 has a key role in the regulation of the oxidative stress response and modulates both migration and retention of hematopoietic stem cells (HSCs) in their niche. The patogenetic importance of Nrf2 depletion in the context of expansion of the hematopoietic progenitor pool in MPNs is discussed with particular focus upon the implications of concomitant downregulation of Nrf2 and CXCR4 for stem cell mobilization.

Polycythemia vera (PV) is characterized by the presence of the JAK2V617F mutation in virtually all patients. Several studies have shown that the JAK2V617F mutational load decreases during treatment with alpha-interferon 2. We report on molecular and histomorphological bone marrow responses in seven PV patients with profound molecular responses during and after long-term treatment with alpha-interferon 2b. All patients obtained a major molecular response (MMR). Subsequently all patients discontinued alpha-interferon and sustained complete hematological remission with a follow-up period of median 10 months (range 4-30 months). Complete normalization of the bone marrow was seen in three of five patients. Long term treatment with IFN2b is able to induce 'minimal residual disease' with very low JAK2 V617F allele burden and may induce profound, and in some patients total, regression of histomorphological bone marrow features of PV. Finally, hematological remissions and major molecular responses can be sustained after discontinuation of long-term treatment with IFN2b.

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