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1.  STAT5 N-domain deleted isoforms are naturally occurring hypomorphs partially rescued in hematopoiesis by transgenic Bcl-2 expression 
Signal transducer and activator of transcription 5 (STAT5) is a critical regulator of normal and leukemic lympho-myeloid development through activation downstream of early-acting cytokines, their receptors, and JAKs. Truncation of STAT5 can be mediated through alternative translation initiation from an internal start codon giving rise to N-terminally deleted isoforms. To determine whether these isoforms could be detected naturally in normal murine tissues, Western blot analyses were performed on heart, lung, brain, spleen, liver, and kidney. Relative expression of full-length to truncated STAT5 was variable among tissues. Since we have previously demonstrated that STAT5abΔN lacks the ability to effectively upregulate pro-survival signals and bcl-2 expression, we used a transgenic mouse approach to next determine whether constitutive expression of human Bcl-2 in STAT5abΔN/ΔN mouse hematopoietic cells could restore normal hematopoiesis. Transgenic H2K-Bcl-2 expression in hypomorphic STAT5abΔN/ΔN mice largely rescued peripheral B and T lymphocyte numbers whereas multilineage donor contribution was only rescued to levels about 10% of normal. At the hematopoietic stem cell level, direct competitive repopulation with H2K-Bcl-2/STAT5abΔN/ΔN against STAT5abΔN/ΔN competitor showed a corrective effect of Bcl-2 expression whether the STAT5abΔN/ΔN genotype was competed as the donor or as the host versus H2K-Bcl-2/STAT5abΔN/ΔN genotype bone marrow cells. Therefore, STAT5abΔN isoforms are heterogeneously expressed and lack key functional activities that can be partially rescued by adding back Bcl-2.
PMCID: PMC4165113  PMID: 25232501
Cytokine signaling; JAK/STAT; hematopoiesis; apoptosis; Bcl-2
2.  The transcription factor Miz-1 is required for embryonic and stress-induced erythropoiesis but dispensable for adult erythropoiesis 
Myc-interacting zinc finger protein 1 (Miz-1) is a BTB/POZ domain transcription factor that regulates complex processes such as proliferation and apoptosis. Constitutively Miz-1-deficient animals arrest embryonic development at E14.5 due to severe anemia and fetal liver cells lacking Miz-1 show a high cell death rate and a significant reduction of mature Ter119+ckit- or Ter119+CD71-/low cells. Consistently, the numbers of BFU-Es and CFU-Es were severely reduced in colony forming assays. Mice with conditional Miz-1 alleles deleted around E14.5 were born at expected ratios, but had reduced numbers of erythrocytes, and showed an increase in reticulocytes and Macro-RBCs in the peripheral blood. When challenged with the hemolytic agent phenylhydrazine (PHZ), Miz-1 deficient mice responded with a severe anemia after 4 days of treatment, but showed a delay in the recovery from this anemia with regard to RBC counts, hematocrit and hemoglobin levels compared to controls. In addition, an accumulation of immature CD71+Ter119+ cells occurred in the bone marrow and spleen of mice lacking a functional Miz-1. We conclude from our studies that Miz-1 is important for erythroid differentiation and development. Moreover, Miz-1 is necessary to maintain a peripheral red blood cell homeostasis in particular in response to hemolysis after oxidative stress.
PMCID: PMC4165114  PMID: 25232500
BTB/POZ domain; transcription factor; Miz-1; erythropoiesis; Epo; STAT5
3.  Multiplex amplification refractory mutation system (MARMS) for the detection of β-globin gene mutations among the transfusion-dependent β-thalassemia Malay patients in Kelantan, Northeast of Peninsular Malaysia 
The aim of this study was to adapt MARMS with some modifications to detect beta mutation in our cohort of thalassemia patients. We focused only on transfusion-dependent thalassemia Malay patients, the predominant ethnic group (95%) in the Kelantanese population. Eight mutations were identified in 46 out of 48 (95.83%) beta thalassemia alleles. Most of the patients (54.2%) were compound heterozygous with co-inheritance Cd 26 (G>A). The frequencies of spectrum beta chain mutation among these patients are presented in Table 2. Among the transfusion dependent beta thalassemia Malay patients studied, 26 patients were found to be compound heterozygous and the main alleles were Cd 26 (G>A). Compound heterozygous mutation of Cd 26 (G>A) and IVS 1-5 (G>C) were 12 (46.2%), Cd 26 (G>A) and Cd 41/42 (TTCT) were 9 (34.6%), Cd 26 (G>A) and IVS 1-1 (G>C) were 2 (7.7%) respectively. Meanwhile the minority were made of a single compound heterozygous of Cd 26 (G>A) and Cd 71/72, Cd 26 (>A) and Cd 17 (A>T), Cd 26 (G>A) and -28 (G>A) respectively. Twenty out of forty six patients were shown to have homozygous of IVS 1-5 (G>C) were 2 (10.0%), Cd 26 (G>A) were 15 (75.0%), Cd 19 (A>G) were 1 (5.0%), and IVS 1-1 (G>T) were 2 (10.0%). The beta chain mutations among the Kelantanese Malays followed closely the distribution of beta chain mutations among the Thais and the Malays of the Southern Thailand. The G-C transition at position 5 of the IVS 1-5 mutation was predominant among the Malay patients. In conclusion, this method has successfully identified the mutation spectrum in our cohort of transfusion-dependent beta thalassemia patients, and this method is equally effective in screening for mutation among thalassemia patients.
PMCID: PMC4165115  PMID: 25232503
MARMS-PCR; β-globin gene; thalassemia; Malay; mutation
4.  Concomitant a novel ALAS2 mutation and GATA1 mutation in a newborn: a case report and review of the literature 
GATA-1, an X-linked gene, encodes a transcription factor that plays a role in erythropoiesis and megakaryopoiesis. GATA-1 mutations have been associated with various diseases, such as X-linked thrombocytopenia. ALAS2 is an X-linked erythroid-specific isoenzyme expressed during erythropoiesis. Mutations of ALAS2 were associated with X-linked sideroblastic anemia. We report a case of newborn twin boy with anemia and thrombocytopenia at birth. A bone marrow biopsy at 4 months of age showed marked dyserythropoiesis, dysmegakaryopoiesis, and rare ringed sideroblasts. Gene sequencing study showed a previously reported mutation in GATA-1 at c.622G>A location (G208R) and a novel ALAS2 mutation at c.1436G>A location (R479Q).
PMCID: PMC4165116  PMID: 25232504
GATA1 mutation; ALAS2 mutation; macrothrombocytopenia; dysmegakaryopoiesis; dyserythropoiesis; ringed sideroblasts
5.  Renal complications of beta-thalassemia major in children 
The success that has been made in the care of patients with thalassemia has led to the emergence of unrecognized complications including several renal abnormalities. Chronic anemia and iron overload as well as the use of iron chelator are believed to lie behind these abnormalities. Many investigators document the presence of tubular dysfunction and abnormalities in glomerular filtration rate in these patients. In this review we will discuss the updates in the diagnosis, pathogenesis and prevention of renal complications of thalassemia.
PMCID: PMC4165117  PMID: 25232499
Children; thalassemia; renal complications
6.  Transfusion-independent β0-thalassemia after bone marrow transplantation failure: proposed involvement of high parental HbF and an epigenetic mechanism 
Currently, bone marrow transplantation is the only curative treatment for β-thalassemia and sickle cell disease. In rare cases, sustained and full fetal hemoglobin production was observed in patients after failure of bone marrow transplantation. This rendered the patients transfusion-free, despite genetic disease and transplant rejection. The mechanisms underlying this phenomenon remain unexplored. We have studied a trio (father-mother-child) in which the affected child became transfusion-independent after rejection of an allogeneic bone marrow graft. Remarkably, we found that his non-thalassemic mother also expressed unusually high levels of γ-globin. High HbF in one of the parents may therefore be of prognostic value in these rare cases. Genotyping of the HBB locus and the HbF quantitative trait loci HBS1L-MYB, KLF1 and BCL11A, and protein expression analysis of KLF1 and BCL11A, failed to explain the increased HbF levels, indicating that an as yet unidentified HbF modifier locus may be involved. We hypothesize that epigenetic events brought about by the transplantation procedure allow therapeutic levels of HbF expression in the child. Potential implications of our observations for reactivation of γ-globin expression and interpretation of the French globin gene therapy case are discussed.
PMCID: PMC4165118  PMID: 25232502
β-thalassemia; bone marrow transplantation; HbF; transfusion-independence; epigenetics; MYB; KLF1; BCL11A; HBB
7.  N-cadherin impedes proliferation of the multiple myeloma cancer stem cells 
Multiple myeloma (MM) is an incurable malignancy of the plasma cells localized to the bone marrow. A rare population of MM cancer stem cells (MM-CSCs) has been shown to be responsible for maintaining the pull of residual disease and to contribute to myeloma relapse. The stem cells are found in a bone marrow niche in contact with the stromal cells that are responsible for maintaining the proliferative quiescence of the MM-CSC and regulate its self-renewal and differentiation decisions. Here we show that both MM and bone marrow stromal cells express N-cadherin, a cell-cell adhesion molecule shown to maintain a pool of leukemic stem cells. Inhibition of N-cadherin using a neutralizing antibody led to an increase in the MM cell proliferation. A decrease in MM cell adhesion to the bone marrow stroma was observed in the first 24 hours of co-culture followed by a 2.3-30-fold expansion of the adherent cells. Moreover, inhibition of N-cadherin led to a 4.8-9.6-fold expansion of the MM-CSC population. Surprisingly, addition of the N-cadherin antagonist peptide resulted in massive death of the non-adherent MM cells, while the viability of the adherent cells and MM-CSCs remained unaffected. Interestingly, the proliferative effects of N-cadherin inhibition were not mediated by the nuclear translocation of β-catenin. Taken together, our findings demonstrate the crucial role of N-cadherin in regulating MM cell proliferation and viability and open an interesting avenue of investigation to understand how structural modifications of N-cadherin can affect MM cell behavior. Our findings suggest that targeting N-cadherin may be a useful therapeutic strategy to treat MM in conjunction with an agent that has anti-MM-CSC activity.
PMCID: PMC3875273  PMID: 24396705
Multiple myeloma; cancer stem cells; N-cadherin
8.  Chronic myelogenous leukemia after postoperative adjuvant S-1 therapy for rectal cancer: a case report 
We report a case in which chronic myelogenous leukemia (CML) developed after postoperative adjuvant S-1 therapy for rectal cancer. A 56-year-old man was diagnosed with rectal adenocarcinoma, which was treated with abdominoperineal resection followed by a year of adjuvant S-1 therapy. At 39 postoperative months, he was diagnosed with CML. Although it remains unclear that CML that develops after treatment involving cytotoxic agents is treatment-related, clinicians should be aware of the possibility of CML developing after S-1 therapy.
PMCID: PMC3875274  PMID: 24396706
Chronic myelogenous leukemia; rectal cancer; fluoropyrimidine; S-1
9.  Granulocytic sarcoma: a systematic review 
Granulocytic sarcoma also called myeloid sarcoma is an extramedullary tumor of immature granulocytic cells. It is a rare entity, and mostly accompanied by acute myeloid leukemia. It is observed during the course of myeloproliferative disorders especially in chronic myeloid leukemia and myelodysplastic syndromes. In some rare circumstances, it is detected before clinical signs of leukemia or other diseases. When the bone marrow biopsy reveals no other hematologic malignancies, the granulocytic sarcoma is described as nonleukemic, primary or isolated. It is observed at any part of the body but the most common locations are soft tissues, bone, peritoneum and lymph nodes. Presenting signs or symptoms are mainly due to mass effect of the tumor and dysfunction of the organ, or the tissue that is affected. The diagnosis is performed by biopsy of the tumor. The tumor consists of immature granulocytic cells, which could be documented by H&E, immunohistochemistry, and flow cytometric methods. Fluorescence in-situ hybridization and molecular analysis are also performed. The optimal time and type of treatment is not clear. Surgery could be an option especially for tumors, which cause organ dysfunction and/or obstruction. Systemic treatment should be considered in all patients because without systemic treatment, relapses and progression to acute myeloid leukemia is the ultimate fate of the disease in many cases. Cytarabine-containing remission-induction chemotherapies have been the most applied therapeutic strategies, but it is not clear whether the consolidation therapies are required or not, and what kind of regimens are appropriate. The role of hematopoietic stem cell transplantation (HSC) as a consolidation regimen is not clear, but, after the relapse of the disease with or without bone marrow involvement, HSC transplantation should be considered in suitable patients after the reinduction performed by AML chemotherapies. There is only limited data about the role of radiotherapy in these patients. It could be used in patients with relapsed disease, organ dysfunction which should be quickly relieved and inadequate response to chemotherapy. The effect of radiotherapy on overall survival is not known. New prospective studies and clinical trials are needed to generate guidelines for the treatment of primary granulocytic sarcomas.
PMCID: PMC3875275  PMID: 24396704
Granulocytic sarcoma; treatment; chemotherapy; leukemia
10.  The Epstein-Barr virus microRNA BART11-5p targets the early B-cell transcription factor EBF1 
Epstein-Barr virus (EBV) is a ubiquitous B-cell trophic herpesvirus associated with a variety of histologically diverse B-cell lymphomas, each associated with specific viral-latency gene expression programs. Initial infection drives resting B-cells to differentiate via an atypical germinal centre reaction into memory B-cells, where the virus resides in a latent state. The mechanisms that underpin this process have yet to be fully elucidated. EBV expresses more than 40 microRNAs (miRNAs). The alternatively spliced BamHI A rightward transcripts (BARTs) are the template for two large miRNA clusters (BARTs A and B), that comprise the majority of all known EBV-miRNAs. Although BART-miRNAs are abundantly expressed in all latency programs, few BART-miRNA targets have been identified and their function is poorly understood. The early B-cell factor 1 (EBF1) was identified using bioinformaticss analysis as a novel target of EBV-miRNA BART11-5p, encoded by BART cluster B. EBF1 is an important B-cell transcription factor that regulates many B-cell specific genes including Pax5, BCR and CD40 and is critical for germinal centre formation. Using luciferase reporter assays and a series of BART-constructs, we confirmed silencing via the EBF1 3’ untranslated region (UTR) and identified the target site as 2137-2159 bp after the stop codon. Results were confirmed following transfection of a BART11-5p mimic, which was able to silence via the predicted target site. Our findings highlight a potential role of BART-miRNAs in the regulation of B-cell differentiation.
PMCID: PMC3755520  PMID: 23997984
EBV; microRNA; BamHI A rightward transcripts; early B-cell transcription factor; B-cell
11.  Changes in molecular biology of chronic myeloid leukemia in tyrosine kinase inhibitor era 
Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease characterized by a reciprocal translocation between long arms of chromosomes 9 and 22 t(9;22) that generates the BCR-ABL fusion gene. If left untreated, newly diagnosed chronic phase CML patients finally progress to accelerated and blastic phase. After the introduction of tyrosine kinase inhibitors (TKIs), treatment strategies of CML changed dramatically. However, the development of resistance to TKIs started to create problems over time. In this review, the current information about CML biology before and after imatinib mesylate treatment is summarized.
PMCID: PMC3755521  PMID: 23997982
Chronic myeloid leukemia; moleculer biology; imatinib mesylate
12.  Treatment of severe steroid resistant acute GVHD with mesenchymal stromal cells (MSC) 
Background: Several studies revealed that MSC from human bone marrow can downregulate graft-versus-host disease (GVHD) after allogeneic HSCT. Methods: Herein we present 50 patients with acute GVHD who got 74 (1-4) MSC infusions for 54 separate episodes of aGVHD. Results: aGVHD was defined as steroid resistant grade IV aGVHD in 42 cases. The major presentation was gastrointestinal GVHD; two (n=18) or more (n=21) systems were involved in the majority of cases. The 1st infusion with MSC was given on day +27 (range, 1 to 136); d+45 (range, +11 to +150) post diagnosis of aGVHD and HSCT, respectively. In 2/3 of the cases treatment was performed with frozen stocked MSCs; in 62 cases early passages (1-3) were used. The median number of infused cells was 1.14±0.47 million per kg in the first injection and up to 4.27 (1.70±1.10) millions in total. The two patients with aggressive liver GVHD received MSCs injections intra hepatic arteries without changes of blood flow or evidence cytolysis, but also without a visible effect. Disease free survival at 3.6 years was 56%. We observed better overall survival in patients with GVHD grade < 4, in responders to the 1st treatment with MSC, and in pediatric group. The multivariate analysis demonstrated independent influence on survival of initial response and younger age. There were no immediate or late toxicity or side effects. Conclusion: Injection of MSCs seems to be a promising and safe treatment of GVHD. The encouraging results obviously should be confirmed in a randomized prospective study.
PMCID: PMC3755522  PMID: 23997985
Mesenchymal stromal cells (MSC); mesenchymal stem cells; hematopoietic stem cell transplantation; graft versus host disease; steroid resistance
13.  Costs and quality of life in patients with myelodysplastic syndromes 
Myelodysplastic syndromes (MDS) encompass a range of myeloid neoplasms characterised by a defect in haematopoietic stem cell maturation, resulting in peripheral cytopenias. As a major consequence, most MDS patients become anaemic, so as to require red blood cell transfusions. To investigate the costs and the impact on quality of life (QOL) of MDS-separately in transfusion-independent (TI) and -dependent (TD) patients-a literature search was conducted. From Medline and Embase, 742 studies were identified, of which 17 were considered eligible. Total medical costs per patient/year range from $ 9,840 to $ 19,811 for the TI condition and from $ 29,608 to $ 51,066 in the TD condition, more than doubling when moving from the former condition to the latter. With regard to QOL, in the transition from TI to TD, QOL could be reduced by half depending on the studies. The TD condition negatively impacts on costs and the QOL of patients with MDS. Therapeutic strategies that reduce transfusion dependence may lead to broad benefits for patients and the community.
PMCID: PMC3755523  PMID: 23997987
Myelodysplastic syndromes; anemia; transfusion dependence; quality of life; medical costs
14.  Detection of immune suppressive neutrophils in peripheral blood samples of cancer patients 
Neutrophils provide first-line defense against infections and are potent effectors in innate and adaptive immunity. Recently neutrophils have been shown to play important roles in multiple antitumor reactions. A subset of mature neutrophils in human systemic inflammation has been identified as a unique circulating population of myeloid cells, which is capable of inhibiting T cell responses. These neutrophils show unique immunophenotype (CD11c bright/CD62L dim/CD11b bright/CD16 bright). This study reports detection of mature neutrophils with similar immunophenotype in the peripheral blood samples of cancer patients using flow cytometry analysis. This population of neutrophils is not detected in peripheral blood samples of normal controls. Thus this finding suggests the involvement of mature neutrophils in antitumor immunity.
PMCID: PMC3755524  PMID: 23997986
Neutrophils; immunosuppressive; cancer; CD62L
15.  Tailoring of chronic lymphatic leukemia therapy 
Chronic lymphocytic leukemia (CLL) remains an incurable disease, with all patients who require therapy destined to relapse and understanding of the pathophysiology of chronic lymphocytic leukemia has advanced significantly. It is now clear that chronic lymphocytic leukemia is a relatively proliferative disorder that requires the help of its microenvironment to be maintained and to progress. The stimulation of the chronic lymphatic leukemia cell occurs in most, if not all, patients through antigen stimulation via the B cell receptors. In addition, there is now a appreciation of the role of the p53 pathway leading to chemoresistance and the elucidation of the molecular and intracellular signaling mechanisms of disease is just beginning to facilitate the development of several targeted small molecules that promise to revolutionize the treatment of Chronic lymphocytic leukemia.
PMCID: PMC3755525  PMID: 23997983
Chronic lymphocytic leukemia; pathophysiology; target therapy
16.  Romiplostim for delayed platelet recovery and secondary thrombocytopenia following allogeneic stem cell transplantation 
Delayed recovery of platelet count post allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been associated with worse transplant outcomes. Thrombopoietic agents have been successfully used in immune mediated thrombocytopenia or thrombocytopenia from bone marrow failure syndromes; however, the experience regarding their use after allo-HSCT is limited. Here we report on the safety and efficacy of romiplostim used in 3 consecutive patients with thrombocytopenia post allogeneic transplantation. Two patients had prolonged platelet recovery due to poor graft function while one had secondary failure of platelet recovery, likely immune mediated, post transplantation. Successful use of such agents post-transplant may improve platelet recovery, decrease rates of complications and potentially improve outcomes.
PMCID: PMC3755526  PMID: 23997988
Post-transplant thrombocytopenia; romiplostim; allogeneic hematopoietic stem cell transplantation
17.  Aging- and activation-induced platelet microparticles suppress apoptosis in monocytic cells and differentially signal to proinflammatory mediator release 
Background: Platelet microparticles (PM) are the most abundant cell-derived microparticles in the blood, and accumulate in thrombo-inflammatory diseases. Platelets produce PM upon aging via an apoptosis-like process and by activation with strong agonists. We previously showed that long-term treatment of monocytic cells with apoptosis-induced PM (PMap) promotes their differentiation into resident macrophages. Here we investigated shorter term effects of various types of PM on monocyte signalling and function. Methods and results: Flow cytometry and scanning electron microscopy revealed that PM formed upon platelet aging (PMap) or ultra-sonication (PMsonic) expressed activated αIIbβ3 integrins and tended to assemble into aggregates. In contrast, PM formed upon platelet activation with thrombin (PMthr) or Ca2+ ionophore (PMiono) had mostly non-activated αIIbβ3 and little aggregate formation, but had increased CD63 expression. PM from activated and sonicated platelets expressed phosphatidylserine at their surface, while only the latter were enriched in the receptors CD40L and CX3CR1. All PM types expressed P-selectin, interacted with monocytic cells via this receptor, and were internalised into these cells. The various PM types promoted actin cytoskeletal rearrangements and hydrogen peroxide production by monocytic cells. Markedly, both aging- and activation-induced PM types stimulated the phosphoinositide 3-kinase/Akt pathway, suppressing apoptosis induced by several agonists, in a P-selectin-dependent manner. On the other hand, the PM types differentially influenced monocyte signalling in eliciting Ca2+ fluxes (particularly PMap) and in releasing secondary mediators (complement factor C5a with PMap, and pro-inflammatory tumour necrosis factor-α with PMthr). Conclusions: In spite of their common anti-apoptotic potential via Akt activation, aging- and activation-induced PM cause different Ca2+ signalling events and mediator release in monocytic cells. By implication, aging and activated platelets may modulate monocyte function in different way by the shedding of different PM types.
PMCID: PMC3649808  PMID: 23675563
Aging; apoptosis; microparticles; monocytes; platelet activation; tumour necrosis factor
18.  A rare der(Y)t(Y;1)(q12;q12) in a patient with post-polycythemic myelofibrosis: a case report 
We describe a case of post-polycythemic myelofibrosis harboring der(Y)t(Y;1)(q12;q12). The patient was a 69-year-old man and was initially diagnosed with polycythemia vera. During the clinical course of his condition, the polycythemia developed into myelofibrosis. Chromosome analysis detected der(Y)t(Y;1)(q12;q12). We discuss the association between der(Y)t(Y;1)(q11~12;q12~21) and tumorigenesis along with a review of literature.
PMCID: PMC3649809  PMID: 23675569
Post-polycythemic myelofibrosis; der(Y)t(Y;1)(q12;q12); chromosomal abnormality
19.  Guidelines and diagnostic algorithm for patients with suspected systemic mastocytosis: a proposal of the Austrian competence network (AUCNM) 
Systemic mastocytosis (SM) is a hematopoietic neoplasm characterized by pathologic expansion of tissue mast cells in one or more extracutaneous organs. In most children and most adult patients, skin involvement is found. Childhood patients frequently suffer from cutaneous mastocytosis without systemic involvement, whereas most adult patients are diagnosed as suffering from SM. In a smaller subset of patients, SM without skin lesions develops which is a diagnostic challenge. In the current article, a diagnostic algorithm for patients with suspected SM is proposed. In adult patients with skin lesions and histologically confirmed mastocytosis in the skin (MIS), a bone marrow biopsy is recommended regardless of the serum tryptase level. In adult patients without skin lesions who are suffering from typical mediator-related symptoms, the basal serum tryptase level is an important diagnostic parameter. In those with slightly elevated tryptase (15-30 ng/ml), additional non-invasive investigations, including a KIT mutation analysis of peripheral blood cells and sonographic analysis, is performed. In adult patients in whom i) KIT D816V is detected or/and ii) the basal serum tryptase level is clearly elevated (> 30 ng/ml) or/and iii) other clinical or laboratory features are suggesting the presence of occult mastocytosis, a bone marrow biopsy should be performed. In the absence of KIT D816V and other indications of mastocytosis, no bone marrow investigation is required, but the patient’s course and the serum tryptase levels are examined in the follow-up.
PMCID: PMC3649810  PMID: 23675567
Mastocytosis; tryptase; KIT D816V; diagnostic algorithm; staging
20.  Immune surveillance and lymphoid malignancy in immunocompromised host 
Immune surveillance is a dynamic process that involves an intact immune system to identify and protect the host against tumor development. The increased understanding of the genetics, infections and hematological malignancies in congenital immune deficiency states supports the concept that impaired T cells and Natural-killer/T cells leads to B-cell lymphoma. Furthermore, severe combined immunodeficient mice are prone to spontaneous tumor development and therefore serve as experimental models. Here we discuss the acquired conditions and mechanisms involved in dysregulation of the immune system that lead to lymphoma. Preemptive strategies to improve immune regulation and response and restore a competent immune system may lead to a decrease in lymphoid malignancies.
PMCID: PMC3649811  PMID: 23675561
Lymphoma; immune surveillance; immune deficiency
21.  MyD88 is involved in myeloid as well as lymphoid hematopoiesis independent of the presence of a pathogen 
MyD88 was originally described as a primary response gene up-regulated during myeloid differentiation after IL-6 induction. Later, MyD88 was shown to be a key molecule necessary for IL1, IL18 and Toll-like receptor signaling. Since these receptors recognize abundantly produced cytokines during infection or molecular patterns of pathogens, MyD88 itself was suggested to be an important regulator of the first line of defense against invading pathogens, including the differentiation and maturation of myeloid cells. Here we describe that MyD88 is important for early and late hematopoietic events that occur independently of antigen under steady-state conditions. In MyD88-deficient mice the earliest alteration in hematopoiesis was found at the level of long-term hematopoietic stem cells. Moreover, we found that MyD88 influences not only the development of the myeloid lineage but also the differentiation of B cells. The B cell defect observed in Btk-deficient mice is further enhanced when both molecules, Btk and MyD88, are not expressed. Therefore, MyD88 affects myeloid as well as lymphoid hematopoiesis. Since Btk and MyD88 deficiencies influence differentially myeloid and lymphoid development, both molecules seem to act in different signaling pathways important for appropriate developmental events during myelo- and lymphopoiesis.
PMCID: PMC3649812  PMID: 23675564
MyD88; Btk; hematopoiesis; myelopoiesis; lymphopoiesis
22.  Treatment of older patients with acute myeloid leukemia (AML): a Canadian consensus 
Patients over age 60 comprise the majority of those diagnosed with acute myeloid leukemia (AML), but treatment approaches in this population are variable, with many uncertainties and controversies. Our group conducted a literature review to summarize the latest information and to develop a consensus document with practical treatment recommendations. We addressed five key questions: selection criteria for patients to receive intensive induction chemotherapy; optimal induction and post-remission regimens; allogeneic hematopoietic stem cell transplantation (HSCT); treatment of patients not suitable for induction chemotherapy; and treatment of patients with prior hematological disorders or therapy-related AML. Relevant literature was identified through a PubMed search of publications from 1991 to 2012. Key findings included the recognition that cytogenetics and molecular markers are major biologic determinants of treatment outcomes in the older population, both during induction therapy and following HSCT. Although disease-specific and patient-specific risk factors for poor outcomes are more common in the older population, age is not in itself sufficient grounds for withholding established treatments, including induction and consolidation chemotherapy. The role of HSCT and use of hypomethylating agents are discussed. Finally, suggested treatment algorithms are outlined, based on these recommendations.
PMCID: PMC3649813  PMID: 23675565
Acute myeloid leukemia; chemotherapy; cytogenetics; prognosis; hematopoietic stem cell transplantation; hypomethylating agent
23.  Absence of BRAF exon 15 mutations in multiple myeloma and Waldenström’s macroglobulinemia questions its validity as a therapeutic target in plasma cell neoplasias 
Purpose: Recent whole genome and/or exome sequencing in a cohort of 32 Multiple Myeloma (MΜ) patients reported the incidence of BRAF mutations at 4%, while in another exome sequencing study, BRAF mutations were reported in up to 13% of cases tested. We ran a confirmatory study by using High Resolution Melting Analysis (HRMA), which is a low-cost, straightforward and sensitive screening test for detection of BRAF exon 15 mutations in MM and Waldenström’s macroglobulinemia (WM) patients, in order to investigate their incidence in every day clinical practice. We considered this investigation to be of clinical relevance following the recent emergence of potent anti-BRAF compounds. Patients and Methods: We used genomic DNA isolated from 31 bone marrow aspirates obtained from 25 MM patients and 3 patients with WM (14 female; 14 male) who signed an informed consent. Patients’ median age was 69 years (range 43-86) and median follow-up time was 45 months. Myeloma subtypes were as follows: 7 IgGκ, 6 IgGλ, 7 IgAλ, 4 IgAλ and 1 non-secretory. The bone marrow plasma cells ranged from 12 to 100% (mean/median value 45%). By International Staging System (ISS) 9/25 patients were stage Ι, 6/25 stage ΙΙ, 7/25 stage ΙΙΙ, while in 3 cases staging information was missing. In 3 MM cases matched paired samples at diagnosis and at relapse were also available. DNA samples were screened using HRMA. HRMA results were confirmed by subsequent ds-bi-directional sequencing (Sanger method) for somatic mutations in exon 15 of BRAF. Results: At a limit of detection ≥2.5% mutant allelic content by HRMA, we did not detect any BRAF mutations in exon 15 in any of our 31 samples. Conclusions: By using HRMA we do not confirm previously reported results. Lack of detection of BRAF exon 15 mutations in our MM and WM series may be related to different sensitivity of the assays used and/or the relatively small sample size. In any case, we consider that existing data should be taken into account when considering the clinical development of BRAF inhibitors in plasma cell neoplasms.
PMCID: PMC3649814  PMID: 23675568
Multiple myeloma; BRAF; mutation; WaldenstrÖm’s macroglobulinemia; high resolution melting analysis
24.  Understanding basic steps to hematopoietic stem cell transplantation evaluation 
We are celebrating one millionth transplant in year 2013! With continued improvement in hematopoietic cell transplantation (HCT) outcome, the indications for HCT continue to grow. Furthermore the sources of stem cells and the number of suitable matches are expanding. At the same time, modified transplantation regimens have facilitated safer procedures despite increase in patient’s age and comorbidies. In the current era, any patient indicated for HCT has a stem cell source and therefore steps to HCT and coordinated pre-transplant care is an integral part of management to improve transplant outcome. This review discusses our approach to the transplant evaluation process and this article will serve as a valuable tool for primary care physicians and referring hematologists/oncologists.
PMCID: PMC3649815  PMID: 23675562
Transplantation; hematological malignancies; preparation; evaluation
25.  Refinement of IKZF1 recombination hotspots in pediatric BCP-ALL patients 
Chromosomal translocations resulting in chimeric fusion genes are prototypic for pediatric leukemia patients. The most known fusions are ETV6-RUNX1 or BCR-ABL1 in B-cell progenitor (BCP)-ALL, and rearrangements of MLL in pediatric ALL and AML. Genome-wide sequencing projects have revealed additional, recurrent gene mutations in B cell malignancies. One of these mutations comprises the IKZF1 gene, encoding the IKAROS transcription factor which is one of the essential transcription factors driving lymphoid development. IKZF1 deletions were first identified by SNP arrays in ALL patients, and later identified with a high prevalence in BCR-ABL1+ patients. IKZF1 deletions turned out to be an independent prognostic marker associated with a poor outcome. Here, we characterized IKZF1 deletions in pediatric BCP-ALL patients by combining MLPA mapping experiments with long distance inverse PCR. The aim of our study was also to compare existing methods with our approach. Our attempt confirmed many of the existing data but revealed a more complex pattern of recombination sites, including a total of 4 recombination hotspots. This extended knowledge was translated into a novel, multiplex PCR assay that allows to perform IKZF1 deletion analyses by using a 2-tube PCR approach.
PMCID: PMC3649816  PMID: 23675566
Childhood leukemia; cancer genetics; gene deletion; IKAROS; IKZF1; leukemia markers

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