bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epigenetic Elimination of Mixed-Lineage Leukemia Leukemic Stem Cells by a Potent Small Molecule PRC2 Inhibitor.
Authors: Wang Jenny Yingzi , Sprod Owen , Haber Michelle , Norris Murray D 
Published: October 2019

Abstract
Abstract 2456
Leukemia carrying a chromosomal translocation involving the mixed-lineage leukemia (MLL) gene is particular resistant to current therapy, and is associated with frequent relapse. Current evidence points towards self-renewing leukemic stem cells (LSC) as the driver of relapse. The eradication of LSC is thought to be critical for successful anti-leukemia therapy. Recent studies suggest that the multi-protein complex polycomb repressive complex 2 (PRC2) is required for MLL-rearranged AML. PRC2 contains the core proteins EZH2, EED and SUZ12, which have intrinsic histone methyltransferase activity specific to trimethylation of histone H3 on lysine 27. It is involved in the epigenetic silencing of tumor suppressor genes (e.g., p16 and p19). In this study we determined the effect of a PRC2-associated inhibitor (hereafter named PAI) on the PRC2 components in LSC isolated from bone marrow cells of mice with established leukemia induced by the MLL-AF9 oncogene. Treatment with PAI (0.1 to 0.5 μM) for 24 hours in culture media depleted protein levels of EZH2 and EED in LSC. Following treatment, quantitative real-time PCR and immunoblotting analysis demonstrated increased mRNA and protein levels of p16 and p19, as well as inhibition of cell cycle progression. PAI treatment also induced a 10-fold increase of apoptosis in LSC. As a consequence, colony formation assays showed that LSC treated for 24 hours with 0.1 μM PAI completely lost their ability to form compact colonies in methylcellulose. We are currently assessing the effects of PAI in in vivo models of MLL-rearranged leukemia where preliminary data indicate that we are able to achieve pharmacologic inhibition of the PRC2 activity. Collectively, these findings indicate that PAI depletes the levels of PRC2 components, and eliminates LSC, thus representing a potentially promising novel treatment for AML.

Disclosures:
No relevant conflicts of interest to declare.
CD34 Expression On the Blasts of Bone Marrow Is a Novel Predictor of Poor Prognosis Independent of FlT3-ITD in Acute Myeloid Leukemia with NPM1-Mutation.
Authors: Zhu Hong-Hu , Liu Yan-Rong , Jiang Hao , Lu Jin , Qin Yazhen , Jiang Qian , Huang Xiaojun 
Published: October 2019

Abstract
Abstract 2491

Background:
Most studies have demonstrated NPM1-mutated acute myeloid leukemia(NPM1m+AML) has a favorable prognosis, especially in the absence of concomitant FLT3-ITD. However, recent studies showed the prognostic heterogeneity of NPM1m+AML. CD34-expression was demonstrated as a poor prognosis factor of adult patients with AML in most previous reports. The strike immunophenotype of NPM1m+AML is regarded as lacking expression of CD34, which accounts for about 75% patients. Whether CD34-expression on the blasts has independent prognostic value in NPM1-m+AML has yet to be clarified. We therefore systematically evaluated the prognostic relevance of CD34 status in the context of NPM1mutation status and clinical features in 71 patients treated at our institution.

Methods:
Seventy-one NPM1m+AML patients were retrospectively analyzed in our center. Immunophenotype of AML were detected by 4 color flow cytometry. NPM1 mutation and FLT3-mutation were detected by PCR.

Results:
The percentage of CD34-expressed blasts of bone marrow ranged from 0.01% to 93.2%. Patients with CD34 expression>7%(according to ROC analysis) had a lower complete remission(CR) rate after 1 course induction, disease-free survival(DFS) and overall survival(OS) compared those with CD34-expression¡Ü7%(CR, 46.4% vs. 81.4%, p=0.0038; 3 years DFS, 26.2% vs. 68.5%, p=0.001; 3 years OS, 24.4% vs.69.1%, p<0.0001). Multivariate analysis revealed CD34-expression as an independent prognostic factor independent of FlT3-ITD for relapse, DFS and OS. We established a new prognostic model based on CD34 and FLT3 status at diagnosis, which could allow dissection of NPM1m+AML into prognostically different three subgroups: CD34>7% and FLT3-ITD, CD34>7%or FLT3-ITD, CD34¡Ü7% and FLT3-WT(3 years DFS of 0 vs. 58.3% vs. 77%, p=0.002; OS of 0 vs. 59.1% vs. 79.9%, p<0.0001 ) .

Conclusions:
We demonstrated for the first time, that CD34-expression on the blasts is a novel poor predictor independent of FlT3-ITD in patients with NPM1-mutation, and established a new prognostic model based on CD34 and FLT3 status at diagnosis, which could allow immediate clinical utility for prognostic stratification and risk-adapted therapeutic choices.

Disclosures:
No relevant conflicts of interest to declare.
A Phase 2 Trial of HQK-1001 (sodium 2,2-dimethylbutyrate), an Oral Fetal Globin Gene Inducer, in HbE-Beta Thalassemia in Thailand
Authors: Fucharoen Suthat , Chaneiam Nattawara , Patthamalai Beer Poramin , Perrine Susan P 
Published: October 2019

Abstract
Abstract 251
Beta thalassemia intermedia (BTI) syndromes are characterized by globin chain imbalance, ineffective erythropoiesis, hemolytic anemia, and have no therapeutic approved for the underlying pathology. Higher fetal globin (HbF) expression can compensate for beta globin deficiency, reduce globin chain imbalance, and ameliorate phenotype within the same genotypes. HQK-1001 (HemaQuest Pharmaceuticals, San Diego, CA) is an orally bioavailable, non-cytotoxic, short-chain fatty acid derivative which induces fetal globin expression in multiple experimental models. In thalassemic erythroid progenitors in vitro, HQK-1001 prolongs STAT-5 phosphorylation and increases expression of the pro-survival protein Bcl-xL. In a Phase I/II dose-escalation trial in BTI, HQK-1001 administered at 10, 20, 30, and 40 mg/kg/day for 8 weeks was well–tolerated, demonstrated a t½ of 9–11 hours, and treatment resulted in an increase in HbF and total hemoglobin (Hgb), with best results observed at 20 mg/kg.
This open-label Phase 2 trial evaluated HQK-1001 administered orally at 20 mg/kg once daily for 26 weeks in adult patients with HbE-β0 thalassemia (NCT01609595). Ten subjects were enrolled, ages 20–36 years, including 7/10 female and 5/10 splenectomized subjects. The beta globin molecular mutations of the subjects, in addition to Codon 26 (G-A), included Codon 41/42 (-TTCT), Codon 17 (A-T), Codon 110 (T-C), and IVS I-I (G-T). At the time of this analysis, 9 of 10 subjects have completed at least 20 weeks of dosing. HbF has increased in all subjects above baseline levels by a mean of 10% (range 4.3% to 20.9%) and total HbF has increased by a mean of 1.07 g/dL, (range 0.52–2.38 g/dL, with positive changes in total HbF observed in 9/10 subjects. Total Hgb has increased by >0.5 g/dL above baseline (mean of 1.27 g/dL, range 0.7 to 2.2 g/dL) in 3 subjects after 3 to 5 months of dosing. Treatment was well-tolerated. There have been no severe drug-related adverse events, no serious adverse events, and no clinically relevant laboratory abnormalities. One subject developed transient proteinuria and edema without changes in renal function 3 weeks following an episode of pharyngitis. This ongoing trial demonstrates consistent induction of fetal globin expression by HQK-1001 at a well-tolerated dose level in subjects with HbE-beta thalassemia.

Disclosures:
Fucharoen: HemaQuest Pharmaceuticals: Research Funding. Perrine:HemaQuest Pharmaceuticals: Equity Ownership, Patents & Royalties.
Clinical Implications of Reticulin Fibrosis of Bone Marrow in De Novo Acute Myeloid Leukemia.
Authors: Tang Tzung-Chih , Chang Hung , Sun Chien-Feng , Shih Lee-Yung , Dunn Po , Wang Po-Nan , Wu Jin-Hou , Kuo Ming-Chung , Lin Tung-Liang , Hung Yu-Shih , Kao Hsiao-Wen 
Published: October 2019

Abstract
Abstract 2585

Background:
Microenvironment of bone marrow (BM) plays an important role to support proliferation, renewal and differentiation of hematopoietic stem cells. Whether the stroma of BM affects leukemic cells with the same manner, or impacts on the prognosis in leukemia patients, has not been fully investigated. Previous studies have described that increased reticulin content in the BM is associated with poor outcome in patients with acute lymphoblastic leukemia, chronic myeloid leukemia and primary myelofibrosis, but there is no cohort study to determine the clinical correlation between degree of reticulin fibrosis of BM and acute myeloid leukemia (AML). To investigate prognostic impact of reticulin fibrosis on de novo AML, 881 patients diagnosed between Jun 1999 to Dec 2011 in Chang Gung Memorial Hospital and treated with anthracycline-containing induction chemotherapy were retrospectively reviewed.

Patients and methods:
According to the grading of reticulin content in the bone marrow, we categorized the 881 patients into four groups: A. BM easily aspirated without biopsy, n = 698; B. Reticulin grade 0, n = 99; C. Reticulin grade 1–2, n = 51; D. Reticulin grade 3–4, n = 33. The induction failure (IF) rate after treatment with induction chemotherapy, the recovery duration of absolute neutrophil count (ANC) greater than 0.5 × 109/L in patients who achieved the first complete remission, the overall survival (OS) and relapse-free survival (RFS) in four groups were analyzed. Based on the cytogenetic or molecular features, 648 of the patients were stratified into unfavorable, intermediate and favorable risk groups, and the clinical significance of reticulin fibrosis of BM were also examined for various risk groups.

Results:
Of the 881 patients, the patients in group D had a statistically higher IF rate (P = 0.0108) and longer ANC recovery duration (P = 0.0008). But the OS and RFS between four groups were not significantly different (P = 0.5146 and 0.3853, respectively). After risk stratified by cytogenetic and molecular analysis, increased reticulin content of BM (group C or D) had an adverse impact on OS in the intermediate and favorable risk groups (P = 0.006 and 0.0215, respectively).

Conclusion:
Reticulin content of BM influences the IF rate and myeloid recovery for the patients of de novo AML, and affects OS in patients with intermediate or favorable risk factors.

Disclosures:
No relevant conflicts of interest to declare.
Increased Risk of Central Venous Catheter Associated Thrombosis in Acute Promyelocytic Leukemia.
Authors: Grisariu Sigal , Spectre Galia , Kalish Yossef , Gatt Moshe E. 
Published: October 2019

Abstract
Abstract 2588

Background:
Patients with acute leukemia and in particular, patients with acute promyelocytic leukemia (APL), are considered to be at high risk for the development of venous thromboembolism. The presence of central venous catheters (CVC) increases the risk of thrombotic complications; however, previous reports have varied as to the frequency of this complication. Current guidelines do not recommend the routine use of prophylactic anticoagulation for patients with CVC.

Design and methods:
We have suspected an increased incidence of CVC thrombosis in patients with APL and therefore conducted a retrospective survey of 473 patients who were treated for acute leukemia at our institution.

Results:
The overall rate of symptomatic CVC thrombosis was 6.8%. We found a significantly (p< 0.001) increased rate of symptomatic CVC thrombosis (32%) in patients with APL as compared with patients with acute lymphocytic leukemia (ALL) and acute myeloid leukemia (AML) (6.4% and 4% respectively) as shown in Figure 1. CVC thrombosis was most prevalent following induction treatment, during the period of recovery of blood counts, and was associated with significantly higher platelet counts in patients with APL compared to other AML patients. We therefore relate this higher thrombosis rate to the disease pro-coagulants, the treatment with all-trans-retinoic-acid and the high platelet counts at the time of induction recovery.
Subsequently, following this observation, we treated 13 newly diagnosed patients with APL with low molecular weight heparin prophylaxis during the induction recovery phase of blood counts. None of these patients had a thrombotic event, nor a bleeding complication.

Conclusions:
Although our treatment group was small, we suggest considering prophylaxis for CVC thrombosis during platelet recovery after induction treatment in patients with APL.

Disclosures:
No relevant conflicts of interest to declare.
Constant Activation of the RAF-MEK-ERK Pathway As a Diagnostic and Therapeutic Target in Hairy Cell Leukemia.
Authors: Tiacci Enrico , Schiavoni Gianluca , Martelli Maria Paola , Boveri Emanuela , Pacini Roberta , Tabarrini Alessia , Zibellini Silvia , Santi Alessia , Pettirossi Valentina , Fortini Elisabetta , Ascani Stefano , Arcaini Luca , Inghirami Giorgio , Paulli Marco , Falini Brunangelo 
Published: October 2019

Abstract
Abstract 2657
The BRAF-V600E mutation defines genetically hairy cell leukemia (HCL) among B-cell leukemias and lymhphomas. In solid tumors, BRAF-V600E is known to aberrantly activate the oncogenic MEK-ERK pathway, and targeted BRAF and/or MEK inhibitors have shown remarkable efficacy in clinical trials of melanoma patients. However, the MEK-ERK pathway status in HCL has not been thoroughly investigated so far. Therefore, as a read-out of MEK-ERK pathway activation, we assessed phospho-ERK expression in 37 HCL patients using immunohistochemistry on routine biopsies and/or Western blotting on purified leukemic cells. Beside confirming the constant presence of BRAF-V600E in all patients, we documented ubiquitous phospho-ERK expression in HCL. Conversely, all 44 HCL-like cases in parallel studied (40 splenic marginal zone lymphoma, 2 HCL-variant and 2 splenic lymphoma/leukemia unclassifiable) were devoid of BRAF-V600E and none expressed phospho-ERK. Lack of phospho-ERK expression was also documented in two exceptionally rare cases of non-HCL CD5-negative B-cell lymphoproliferative disorders not otherwise specifiable that were previously described to harbour the BRAF-V600E mutation on allele-specific PCR (Arcaini et al, Blood 2012;119:188–191), pointing to the presence of this mutation in only a small part of the leukemic clone in these cases. Our findings support the use of phospho-ERK immunohistochemistry in the differential diagnosis between HCL and HCL-like neoplasms and establish the MEK-ERK pathway as a rational therapeutic target in HCL.

Disclosures:
Tiacci: Not applicable: Dr. Tiacci filed a patent for the clinical use of BRAF mutations as biomarkers of HCL. Other. Inghirami:OncoEthix SA: Research Funding. Falini:Not applicable: Dr. Falini filed a patent for the clinical use of BRAF mutations as biomarkers of HCL. Other.
Ivig, but Not a Monoclonal Anti-RBC Antibody, Requires the Presence of Gr-1+ Cells to Ameliorate Immune Thrombocytopenia in a Murine Model
Authors: Crow Andrew R. , Lazarus Alan H 
Published: October 2019

Abstract
Abstract 268
Although there are many theories as to the mechanism of action of IVIg in the treatment of autoimmune disease, the exact pathway by which IVIg functions remains unclear. Many cell populations have been implicated in the IVIg pathway, including dendritic cells, which are considered to be one of the central initiators of IVIg effects, and macrophages, which are involved in platelet destruction. In addition, there is evidence from several groups that additional intermediary cell types may be involved. IVIg administration can induce a suppressive effect on peripheral blood neutrophil counts in ITP patients. In fact, alloimmunized thrombocytopenic patients, who display low neutrophil counts, do not respond to IVIg therapy.
Here, we questioned whether Gr-1+cells (consisting primarily of neutrophils) are a critical cell type required for IVIg function, in a murine model of ITP. Another IVIg product which has ameliorative effects similar to IVIg but appears to function via a different mechanism is anti-D. We have previously shown that IVIg and a monoclonal antibody with “anti-D like” activity, TER-119, can successfully ameliorate thrombocytopenia in a murine model of ITP. In human patients as well as murine models of ITP, these 2 therapeutics appear to function via different mechanisms. Some work has shown that IVIg and anti-D work by the same, or overlapping mechanism, while other work shows a notable difference in that IVIg can cause neutropenia under conditions where it works to ameliorate autoimmune inflammation.
Mice pretreated with 50 mg IVIg (∼2g/kg), or 50 ug TER-119 thirty min prior to administration of anti-platelet antibody MWReg30, show protection from thrombocytopenia compared with untreated mice. To assess the potential role for Gr-1+ cells in IVIg vs TER-119 mediated amelioration of murine ITP, we used RB6-8C5, a well described rat antibody for Gr-1+ cell depletion. Mice were injected with RB6-8C5 or control rat IgG 24 hr prior to thrombocytopenia induction. Mice pretreated with RB6-8C5 failed to respond to IVIg therapy compared with control mice. In contrast, Gr-1+ cell depletion had no effect on the ability of TER-119 to ameliorate the thrombocytopenia. This suggests that Gr-1+ cells likely play an essential role in IVIg function. In contrast, TER-119, does not depend on the presence of Gr-1+cells, suggesting that the mechanisms of action for IVIg and RBC specific antibodies are different for this requirement.
In line with these observations, it has been observed that IVIg can modulate neutrophil activity, suggesting that in the murine ITP model, IVIg may function through a neutrophil dependent pathway. Experiments using more specific granulocyte antibodies will help ascertain whether neutrophils or some other Gr-1+ cell population is involved in IVIg function.

Disclosures:
No relevant conflicts of interest to declare.
Mutational Status of Splenic Marginal Zone Lymphoma Revealed by Whole Exome Sequencing.
Authors: Martinez Nerea , Varela Ignacio , Vaque Jose P. , Derdak Sophia , Beltran Sergi , Mollejo Manuela , Sanchez-Beato Margarita , Cereceda Laura , Bayes Monica , Gut Marta , Oscier David , Rodriguez-Peralto Jose L. , Sole Francesc , Fraga Maximo , Garcia Juan F. , Sebastian Elena , Gut Ivo G. , Piris Miguel A. 
Published: October 2019

Abstract
Abstract 2698

Background:
Splenic marginal zone lymphoma (SMZL) is a small B cell neoplasm whose molecular pathogenesis is still unknown. It has a relatively indolent course, but a fraction of the cases may show an aggressive behavior. The lack of comprehensive molecular analysis for SMZL precludes the development of targeted therapy. Here we studied the mutational status of 6 SMZL samples using Whole Exome Next Generation Sequencing.

Methods:
Genomic DNA was extracted from splenic tumor or peripheral blood samples and oral mucosa as the corresponding non-tumor control. Whole exome sequencing was performed at CNAG (Barcelona, Spain) following standard protocols for high-throughput paired-end sequencing on the Illumina HiSeq2000 instruments (Illumina Inc., San Diego, CA). The variant calling was performed using an in house written software calling potential mutations showing a minimum independent multi-aligner evidence.

Results:
We performed paired-end-76pb whole exome sequencing on 6 SMZL samples and the corresponding normal counterpart. Three of the samples corresponded to CD19 isolated cells from peripheral blood, while other three corresponded to spleen freshly frozen tissue. The mean coverage obtained was 104.07 (82.46–119.59) with a mean of 91.41% (90.41–93.73) of bases with at least 15× coverage. After filtering, 237 substitutions and 21 indels where obtained. No recurrent variation was found. Six of the variations found here were already described in other malignancies. Variations were classified into silent (75), missense (147), nonsense (8), and essential splice (5), according to their potential functional effect, and into tolerated (54) and deleterious (76) according to the “variant effect predictor” tool of Ensembl Genome Browser.
Whole exome sequencing permitted us to identify variations in several genes of TLR/NFkB pathway (Myd88, Peli3), BCR (Myd88, Arid3A) or signal transduction (ARHGAP32), essential pathways for B-cell differentiation. These variations and other involving selected genes, such as the Bcl6 repressor BCOR, were validated by capillary sequencing.
These results were confirmed and expanded in a second series of 10 new cases by exome sequencing.

Conclusions:
SMZL samples contain somatic mutation involving genes regulating BCR signaling, TLR/NFKB pathways and chromatin remodeling.

Disclosures:
No relevant conflicts of interest to declare.
Growth Hormone – Insulin-Like Growth Factor –I (IGF-I) Axis and Bone Mineral Density In Adults With Thalassemia Major (TM)
Authors: Yassin Mohamed A. , Soliman Ashraf T , Desanctis Vincenzo 
Published: October 2019

Abstract
Bone disease and short stature are frequent clinical features of patients with beta-thalassaemia major. Dysfunction of the GH-IGF-1 axis has been described in many thalassaemic children and adolescents with short stature and reduced growth velocity.
Assessment of the GH-IGF-1 axis in short adults with TM after attainment of final height may be required to select those who are candidates for replacement therapy and to prevent the development of bone disease. The aim of our study was to investigate GH secretion in adult thalassaemic patients in relation to their bone mineral density (BMD) and serum ferritin concentrations.

Patients and methods
We performed clonidine stimulation test in 30 thalassaemic patients (18 males, 12 females) with a mean age of 31.5 +/- 7.2 years. The cut-off level for GH response was set at 7 microg/l, according to the literature. Serum ferritin, IGF-1, liver enzymes, alkaline phosphatase (ALP) and and type1 Collagen CarboxyTelopeptide (CCT1) were also determined.

Results
We diagnosed GH deficiency (GHD) in 12 patients (40 %) and IGF-I deficiency (IGF-I SDS < -2) was diagnosed in 20 patients (67 %). Adult patients with TM had significantly decreased IGF-I concentrations and bone mineral density (BMD) at the femur neck and lumbar spine compared to normal controls. Thalassemic patients with GHD and IGF-I deficiency had significantly lower BMD T score at the lumbar spine compared to patients with normal GH and IGF-I levels. Thalassemic patients had higher serum CCT1 concentrations compared to normal controls. Peak GH levels were correlated significantly with IGF- I concentrations and IGF-I levels were correlated significantly with the height SDS (HtSDS) of thalassemic patients. Neither GH peak nor IGF-I concentrations were correlated to serum ferritin concentrations.

Conclusions
We conclude that GH status should be tested in adult thalassaemic patients especially those with short stature and/or decreased BMD. If the diagnosis of adult GHD is established, GH treatment may be considered for possible improvement of bone mineral density and heart function in thalassaemic patients.

Disclosures:
No relevant conflicts of interest to declare.