Different niches for stem cells carrying the same oncogenic driver affect pathogenesis and therapy response in myeloproliferative neoplasms.

Aging facilitates the expansion of hematopoietic stem cells (HSCs) carrying clonal hematopoiesis-related somatic mutations and the development of myeloid malignancies, such as myeloproliferative neoplasms (MPNs). While cooperating mutations can cause transformation, it is unclear whether distinct bone marrow (BM) HSC-niches can influence the growth and therapy response of HSCs carrying the same oncogenic driver. Here we found different BM niches for HSCs in MPN subtypes. JAK-STAT signaling differentially regulates CDC42-dependent HSC polarity, niche interaction and mutant cell expansion. Asymmetric HSC distribution causes differential BM niche remodeling: sinusoidal dilation in polycythemia vera and endosteal niche expansion in essential thrombocythemia. MPN development accelerates in a prematurely aged BM microenvironment, suggesting that the specialized niche can modulate mutant cell expansion. Finally, dissimilar HSC-niche interactions underpin variable clinical response to JAK inhibitor. Therefore, HSC-niche interactions influence the expansion rate and therapy response of cells carrying the same clonal hematopoiesis oncogenic driver.

Ruxolitinib Versus Best Available Therapy for Polycythemia Vera Intolerant or Resistant to Hydroxycarbamide in a Randomized Trial.

PURPOSE: Polycythemia vera (PV) is characterized by JAK/STAT activation, thrombotic/hemorrhagic events, systemic symptoms, and disease transformation. In high-risk PV, ruxolitinib controls blood counts and improves symptoms. PATIENTS AND METHODS: MAJIC-PV is a randomized phase II trial of ruxolitinib versus best available therapy (BAT) in patients resistant/intolerant to hydroxycarbamide (HC-INT/RES). Primary outcome was complete response (CR) within 1 year. Secondary outcomes included duration of response, event-free survival (EFS), symptom, and molecular response. RESULTS: One hundred eighty patients were randomly assigned. CR was achieved in 40 (43%) patients on ruxolitinib versus 23 (26%) on BAT (odds ratio, 2.12; 90% CI, 1.25 to 3.60; P = .02). Duration of CR was superior for ruxolitinib (hazard ratio [HR], 0.38; 95% CI, 0.24 to 0.61; P < .001). Symptom responses were better with ruxolitinib and durable. EFS (major thrombosis, hemorrhage, transformation, and death) was superior for patients attaining CR within 1 year (HR, 0.41; 95% CI, 0.21 to 0.78; P = .01); and those on ruxolitinib (HR, 0.58; 95% CI, 0.35 to 0.94; P = .03). Serial analysis of JAK2V617F variant allele fraction revealed molecular response was more frequent with ruxolitinib and was associated with improved outcomes (progression-free survival [PFS] P = .001, EFS P = .001, overall survival P = .01) and clearance of JAK2V617F stem/progenitor cells. ASXL1 mutations predicted for adverse EFS (HR, 3.02; 95% CI, 1.47 to 6.17; P = .003). The safety profile of ruxolitinib was as previously reported. CONCLUSION: The MAJIC-PV study demonstrates ruxolitinib treatment benefits HC-INT/RES PV patients with superior CR, and EFS as well as molecular response; importantly also demonstrating for the first time, to our knowledge, that molecular response is linked to EFS, PFS, and OS.

Survey of UK histopathology consultants' attitudes towards academic and molecular pathology.

OBJECTIVE: Academic pathology is facing a crisis; an ongoing decline in academic pathology posts, a paucity of academic pathologist's in-training and unfilled posts at a time when cellular pathology departments are challenged to deliver increasing numbers of molecular tests. The National Cancer Research Institute initiative in Cellular & Molecular Pathology commissioned a survey to assess attitudes of cellular pathology consultants towards research in order to understand barriers and identify possible solutions to improve this situation. As cellular pathology is encompassing an increasing number of diagnostic molecular tests, we also surveyed the current approach to and extent of training in molecular pathology. METHODS: The survey was distributed to all UK-based consultant pathologists via the Pathological Society of Great Britain & Ireland and Royal College of Pathologist networks. Heads of Department were contacted separately to obtain figures for number of academic training and consultant posts. RESULTS: 302 cellular pathologists completed the survey which represents approximately 21% of the total cellular histopathology workforce. Most respondents (89%) had been involved in research at some point; currently, 22% were undertaking research formally, and 41% on an informal basis. Of those previously involved in research, 57% stopped early in their consultant career. The majority of substantive academic posts were Professors of which 60% had been in post for >20 years. Most respondents (84%) used molecular pathology in diagnostic work, independent of where they worked or the length of time in post. Notably, 53% of consultants had not received molecular pathology training, particularly more senior consultants and consultants in district general hospitals. CONCLUSIONS: The survey reveals that the academic workforce is skewed towards senior individuals, many of whom are approaching retirement, with a missing cohort of 'junior consultant' academic pathologists to replace them. Most pathologists stop formal research activity at the beginning of a consultant career. While molecular pathology is an increasing part of a pathologist's workload, the majority of consultant cellular pathologists have not received any formal molecular training.

Hydroxycarbamide Plus Aspirin Versus Aspirin Alone in Patients With Essential Thrombocythemia Age 40 to 59 Years Without High-Risk Features.

PURPOSE: Cytoreductive therapy is beneficial in patients with essential thrombocythemia (ET) at high risk of thrombosis. However, its value in those lacking high-risk features remains unknown. This open-label, randomized trial compared hydroxycarbamide plus aspirin with aspirin alone in patients with ET age 40 to 59 years and without high-risk factors or extreme thrombocytosis. PATIENTS AND METHODS: Patients were age 40 to 59 years and lacked a history of ischemia, thrombosis, embolism, hemorrhage, extreme thrombocytosis (platelet count ≥ 1,500 × 109/L), hypertension, or diabetes requiring therapy. In all, 382 patients were randomly assigned 1:1 to hydroxycarbamide plus aspirin or aspirin alone. The composite primary end point was time to arterial or venous thrombosis, serious hemorrhage, or death from vascular causes. Secondary end points were time to first arterial or venous thrombosis, first serious hemorrhage, death, incidence of transformation, and patient-reported quality of life. RESULTS: After a median follow-up of 73 months and a total follow-up of 2,373 patient-years, there was no significant difference between the arms in the likelihood of patients reaching the primary end point (hazard ratio, 0.98; 95% CI, 0.42 to 2.25; P = 1.0). The incidence of significant vascular events was low, at 0.93 per 100 patient-years (95% CI, 0.61 to 1.41). There were also no differences in overall survival; in the composite end point of transformation to myelofibrosis, acute myeloid leukemia, or myelodysplasia; in adverse events; or in patient-reported quality of life. CONCLUSION: In patients with ET age 40 to 59 years and lacking high-risk factors for thrombosis or extreme thrombocytosis, preemptive addition of hydroxycarbamide to aspirin did not reduce vascular events, myelofibrotic transformation, or leukemic transformation. Patients age 40 to 59 years without other clinical indications for treatment (such as previous thrombosis or hemorrhage) who have a platelet count < 1,500 × 109/L should not receive cytoreductive therapy.

Management of polycythaemia vera: a critical review of current data.

Polycythaemia vera (PV) is a chronic blood cancer; its clinical features are dominated by myeloproliferation (erythrocytosis, often leucocytosis and/or thrombocytosis) and a tendency for thrombosis and transformation to myelofibrosis or acute myeloid leukaemia. In the past 10 years the pathophysiology of this condition has been defined as JAK/STAT pathway activation, almost always due to mutations in JAK2 exons 12 or 14 (JAK2 V617F). In the same time period our understanding of the optimal management of PV has expanded, most recently culminating in the approval of JAK inhibitors for the treatment of PV patients who are resistant or intolerant to therapy with hydroxycarbamide. It has also been demonstrated that life expectancy for many patients with PV is not normal, nor is their quality of life. We critically explore these findings and discuss their impact. In addition, we highlight persisting gaps in our current management strategy; for example, what is the optimal first line cytoreductive therapy and, indeed, which patients need cytoreductive drugs.

How we diagnose and treat essential thrombocythaemia.

The approach to the diagnosis and management of essential thrombocythaemia (ET) is steadily changing, influenced by advances in molecular biology, data from clinical trials and retrospective analyses of patient cohorts. In the past decade options for clinical management largely remain unchanged, but who we treat, and with what target in mind, is evolving. A further area of change is recognition of symptoms that may be associated with ET, as well as other myeloproliferative neoplasms, and that potential options for their management are becoming available. Judicious and careful diagnosis is increasingly a fundamental key to successful management followed by cytoreductive therapy in a subset of patients. In this review we demonstrate our management strategies for ET using a case-based format.

The prognosis of MYC translocation positive diffuse large B-cell lymphoma depends on the second hit.

A proportion of MYC translocation positive diffuse large B-cell lymphomas (DLBCL) harbour a BCL2 and/or BCL6 translocation, known as double-hit DLBCL, and are clinically aggressive. It is unknown whether there are other genetic abnormalities that cooperate with MYC translocation and form double-hit DLBCL, and whether there is a difference in clinical outcome between the double-hit DLBCL and those with an isolated MYC translocation. We investigated TP53 gene mutations along with BCL2 and BCL6 translocations in a total of 234 cases of DLBCL, including 81 with MYC translocation. TP53 mutations were investigated by PCR and sequencing, while BCL2 and BCL6 translocation was studied by interphase fluorescence in situ hybridization. The majority of MYC translocation positive DLBCLs (60/81 = 74%) had at least one additional genetic hit. In MYC translocation positive DLBCL treated by R-CHOP (n = 67), TP53 mutation and BCL2, but not BCL6 translocation had an adverse effect on patient overall survival. In comparison with DLBCL with an isolated MYC translocation, cases with MYC/TP53 double-hits had the worst overall survival, followed by those with MYC/BCL2 double-hits. In MYC translocation negative DLBCL treated by R-CHOP (n = 101), TP53 mutation, BCL2 and BCL6 translocation had no impact on patient survival. The prognosis of MYC translocation positive DLBCL critically depends on the second hit, with TP53 mutations and BCL2 translocation contributing to an adverse prognosis. It is pivotal to investigate both TP53 mutations and BCL2 translocations in MYC translocation positive DLBCL, and to distinguish double-hit DLBCLs from those with an isolated MYC translocation.

Resolution of bone marrow fibrosis in a patient receiving JAK1/JAK2 inhibitor treatment with ruxolitinib.

UNLABELLED: Ruxolitinib, a JAK1/JAK2 inhibitor, is currently the only pharmacological agent approved for the treatment of myelofibrosis. Approval was based on findings from two phase 3 trials comparing ruxolitinib with placebo (COMFORT-I) and with best available therapy (COMFORT-II) for the treatment of primary or secondary myelofibrosis. In those pivotal trials, ruxolitinib rapidly improved splenomegaly, disease-related symptoms, and quality of life and prolonged survival compared with both placebo and conventional treatments. However, for reasons that are currently unclear, there were only modest histomorphological changes in the bone marrow, and only a subset of patients had significant reductions in JAK2 V617F clonal burden. Here we describe a patient with post-polycythemia vera myelofibrosis who received ruxolitinib at our institution (Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom) as part of the COMFORT-II study. While on treatment, the patient had dramatic improvements in splenomegaly and symptoms shortly after starting ruxolitinib. With longer treatment, the patient had marked reductions in JAK2 V617F allele burden, and fibrosis of the bone marrow resolved after approximately 3 years of ruxolitinib treatment. To our knowledge, this is the first detailed case report of resolution of fibrosis with a JAK1/JAK2 inhibitor. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00934544.

Guideline for the diagnosis and management of myelofibrosis.

The guideline group regarding the diagnosis and management of myelofibrosis was selected to be representative of UK-based medical experts, together with a contribution from a single expert from the USA. MEDLINE and EMBASE were searched systematically for publications in English from 1966 until August 2011 using a variety of key words. The writing group produced the draft guideline, which was subsequently revised by consensus of the members of the General Haematology and Haemato-oncology Task Forces of the British Committee for Standards in Haematology (BCSH). The guideline was then reviewed by a sounding board of UK haematologists, the BCSH and the British Society for Haematology Committee and comments incorporated where appropriate. The criteria used to state levels and grades of evidence are as outlined in the Procedure for Guidelines commissioned by the BCSH; the 'GRADE' system was used to score strength and quality of evidence. The objective of this guideline is to provide healthcare professionals with clear guidance on the investigation and management of primary myelofibrosis, as well as post-polycythaemic myelofibrosis (post-PV MF) and post-thrombocythemic myelofibrosis (post-ET MF) in both adult and paediatric patients.

Granulomatosis with polyangiitis involves sustained mucosal inflammation that is rich in B-cell survival factors and autoantigen.

OBJECTIVE: Granulomatosis with polyangiitis (GPA) is a rare chronic autoimmune disease that may be triggered by upper airway infection. ANCAs specific for PR3 that is expressed by activated neutrophils and macrophages are associated with GPA. Our aim was to investigate regional immune mechanisms that might induce or support the autoimmune response in GPA. METHODS: Biopsy samples from 77 patients including 8 with GPA were studied by immunohistochemistry. B-cell homing subsets in blood samples from 16 patients with GPA and 11 healthy controls were studied by FACS. The distribution of B-cell clones was searched in paired biopsies and blood samples from one patient by analysing immunoglobulin heavy chain gene (IGH) junctional sequences. RESULTS: Activated B cells were located alongside PR3-expressing cells and B-cell survival factors BAFF and APRIL in mucosa from patients with GPA. We detected APRIL production by the granulomas and giant cells. B cells were proliferating in all cases and persistent for 5 years in biopsies obtained from one patient. However, there was no evidence of B-cell clones from the mucosal biopsies circulating in peripheral blood in GPA or any numerical or proportional change in B-cell subsets expressing markers of regional homing in blood in GPA. CONCLUSIONS: Our study illustrates chronically activated B cells alongside autoantigens and B-cell survival factors in the mucosa in GPA.

Revised guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant*.

The British Committee for Standards in Haematology first produced guidelines for the diagnosis and management of hairy cell leukaemia and hairy cell leukaemia variant in 2000. This revision updates those guidelines and covers the areas of diagnosis, treatment and assessment of response to therapy.

Fluorescence in situ hybridisation analysis of formalin-fixed paraffin-embedded tissue sections in the diagnostic work-up of non-Burkitt high grade B-cell non-Hodgkin's lymphoma: a single centre's experience.

AIMS: In recent years the genetic aberrations associated with diffuse large B-cell lymphoma and the new subtype described in the 2008 revision of the WHO classification, 'B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma' have been increasingly well defined. Recurrent genetic abnormalities include rearrangements involving MYC (8q24), BCL2 (18q21) and BCL6 (3q27); as the prognostic and therapeutic implications associated with these abnormalities are clarified their accurate identification at diagnosis is becoming increasingly critical. We describe our experience of using a panel of fluorescence in situ hybridisation (FISH) probes on formalin-fixed paraffin-embedded tissue sections in the diagnostic work-up of 162 patients with non-Burkitt high grade B-cell non-Hodgkin's lymphomas (HG-BNHL). METHODS: BCL6, IGH-BCL2 and MYC status were determined prospectively in sequential patients presenting with HG-BNHL, with respect to the presence of rearrangements and copy number changes. Small numbers of samples were analysed retrospectively or were studied at relapse in previously untested patients. RESULTS: FISH analysis was successful in 160/162 (99%) cases, with abnormalities detected in 118/160 (74%). CONCLUSIONS: FISH analysis of formalin-fixed paraffin-embedded tissue sections is a highly reproducible technique with an excellent success rate for the detection of genetic abnormalities which will play an increasingly important role in improving risk stratification of patients with HG-BNHL.

Pitfalls in bone marrow pathology: avoiding errors in bone marrow trephine biopsy diagnosis.

Avoiding errors in the histological interpretation of bone marrow trephine biopsy specimens requires an unprecedented degree of collaboration between histopathologists, haematologists, specimen requesters, specimen takers, laboratory technical staff and other scientific staff. A specimen of good quality, with full, relevant clinical information is the essential starting point. This must then be processed optimally and investigated appropriately, involving immunophenotyping and molecular testing when needed. A wide range of pathologies may involve bone marrow haemopoietic and stromal components, and a systematic approach to analysing each of the components in turn is required to avoid overlooking abnormalities; correlation with bone marrow cells aspirated in parallel is particularly important. Final interpretation should be a synthesis of the histological findings with information from such haematological and other investigations, interpreted with due regard to clinical context.

Pitfalls in lymphoma pathology: avoiding errors in diagnosis of lymphoid tissues.

The complexity involved in the histological interpretation of lymph nodes and other lymphoid tissue specimens suspected of harbouring lymphoma is underappreciated. As with other histology specimens, the quality of sections and background information are crucial but so, increasingly, is the appropriate use of immunocytochemistry and a variety of molecular analyses. Within the UK National Health Service, progressive regional centralisation is ongoing, to ensure access to specialist expertise and a full range of testing beyond traditional stains. This is to be welcomed but there remains a need to maintain skills in smaller district hospitals, to ensure lymphoma recognition in unexpected circumstances, to permit clinically useful interim diagnoses when needed urgently and to sustain training in haematopathology among junior pathologists. In this review a range of potential pitfalls in lymphoid tissue pathology is outlined, arising at all stages from specimen preparation to reporting. Knowledge of such pitfalls, some of which are common while others are rare but of vital clinical importance, should help increase confidence in lymphoma diagnosis among histopathologists.

Survival outcomes and prognostic factors in mycosis fungoides/Sézary syndrome: validation of the revised International Society for Cutaneous Lymphomas/European Organisation for Research and Treatment of Cancer staging proposal.

PURPOSE: We have analyzed the outcome of mycosis fungoides (MF) and Sézary syndrome (SS) patients using the recent International Society for Cutaneous Lymphomas (ISCL)/European Organisation for Research and Treatment of Cancer (EORTC) revised staging proposal. PATIENTS AND METHODS: Overall survival (OS), disease-specific survival (DSS), and risk of disease progression (RDP) were calculated for a cohort of 1,502 patients using univariate and multivariate models. RESULTS: The mean age at diagnosis was 54 years, and 71% of patients presented with early-stage disease. Disease progression occurred in 34%, and 26% of patients died due to MF/SS. A significant difference in survival and progression was noted for patients with early-stage disease having patches alone (T1a/T2a) compared with those having patches and plaques (T1b/T2b). Univariate analysis established that (1) advanced skin and overall clinical stage, increased age, male sex, increased lactate dehydrogenase (LDH), and large-cell transformation were associated with reduced survival and increased RDP; (2) hypopigmented MF, MF with lymphomatoid papulosis, and poikilodermatous MF were associated with improved survival and reduced RDP; and (3) folliculotropic MF was associated with an increased RDP. Multivariate analysis established that (1) advanced skin (T) stage, the presence in peripheral blood of the tumor clone without Sézary cells (B0b), increased LDH, and folliculotropic MF were independent predictors of poor survival and increased RDP; (2) large-cell transformation and tumor distribution were independent predictors of increased RDP only; and (3) N, M, and B stages; age; male sex; and poikilodermatous MF were only significant for survival. CONCLUSION: This study has validated the recently proposed ISCL/EORTC staging system and identified new prognostic factors.