Jumping Translocation of Homogeneously Staining Region Hsr(11q) in An Erythroid Leukemia: Identification of Amplified Regions by Fluorescence Hybridization, M-FISH and M-Banding.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4890-4890
Author(s):  
Catherine Helias ◽  
Carine Gervais ◽  
Eric Jeandidier ◽  
Bruno Lioure ◽  
Laurent Mauvieux
Keyword(s):  
Hematological Malignancies ◽  
Conflicts Of Interest ◽  
Erythroid Cell ◽  
Specific Gene ◽  
Complex Karyotype ◽  
Chromosome 11 ◽  
Hematological Neoplasms ◽  
Selective Growth Advantage ◽  
Blast Cells ◽  
Conventional Cytogenetics

Abstract Abstract 4890 Gene amplification is a mechanism whereby a tumor cell can increase the copy number of specific gene sequences and gain a proliferative advantage. Although amplifications are common in solid tumors, they are relatively rare in hematological neoplasms. We report here on a patient with an acute erythroid leukemia and a jumping translocation of a hsr(11q) in a complex karyotype, without MLL amplification. The patient was 40 years old when he was admitted for asthenia, peripheral blood showing pancytopenia (Hb=111G/L; neutrophils= 0.23 G/L; platelets 92 G/L), without circulating blast cells. Bone marrow was hypercellular with the presence of more than 50% of erythroid precursors and more than 20% of myeloid blast cells in non-erythroid cell population, leading to the diagnosis of erythroblastic acute leukemia. A marked dysgranulopoiesis was also detected. Conventional cytogenetics showed a complex karyotype with a del(5q), a unbalanced t(7;17) leading to partial 7q deletion and homogeneously staining regions (hsr). Fluorescence in situ hybridization confirmed the del(5q), and showed that TP53 was not deleted in the t(7;17). Multi-FISH (M-FISH) pointed out that the hsr consisted of chromosome 11 and was implicated in 3 different translocations with 3 different partner chromosomes in 3 different clones. To further characterize the amplicon and determine which bands were implicated, we used a chromosome 11 m-band probe. It revealed that the bands implicated are the same on the der(3), der(12) and der(20) and are localized between 11q23.3 and 11q25. A series of BAC probes showed that different genes, present in these regions, were amplified: ETS1, FLI1, KCNJ5, NFRKB, SNX19, HNT, OPCM, but not MLL. Amplifications of chromosome 11q usually includes MLL, but more telomeric amplicons have also been reported in AML and myelodysplatic syndromes (MDS). A very close 11q amplification was identified in 3 AML/MDS cases (Crossen et al, 1999; Tyybäkinoja et al, 2006). Also, the ETS1 oncogene was found to be rearranged and 30-fold amplified in a case of acute myelomonocytic leukaemia, in which an hsr occurred on 11q23 (Rovigatti et al, 1986). The role of chromosomal amplifications in leukemia is unclear, but it has been suggested that they are associated with rapid disease progression and short survival. Jumping translocations are an unusual phenomenon and have been rarely reported in hematological malignancies. Whether jumping translocations play a role in tumor genesis or confer a selective growth advantage on tumor cells is unknown. The combination of hsr and jumping translocations as described here are very rare in hematological malignancies. The cases of the literature (Yoshida et al, 1999) and the one presented here suggest that the 11q24-q25 region may harbor new candidate oncogenes, together with unusual chromosomal mechanisms. Disclosures: No relevant conflicts of interest to declare.

Monosomal Karyotype in MDS and Secondary AML: Do Autosomal Monosomies Have the Same Poor Prognostic Impact As Monosomy 5 and 7?

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4867-4867
Author(s):  
Paolo Bernasconi ◽  
Marina Boni ◽  
Marianna Rossi ◽  
Rita Zappatore ◽  
Irene Dambruoso ◽  
...  
Keyword(s):  
Disease Progression ◽  
Median Time ◽  
Median Survival ◽  
Conflicts Of Interest ◽  
Single Agent ◽  
Prognostic Significance ◽  
Prognostic Impact ◽  
Complex Karyotype ◽  
Cell Percentage ◽  
Conventional Cytogenetics

Abstract Abstract 4867 Background: A monosomal karytype (MK) is defined by the presence of at least two or more distinct autosomal monosomies or an autosomal monosomy along with a structural defect. In AML this cytogenetic pattern has a very well-known poor prognostic significance independently of the specific chromosome involved. Currently, in MDS this negative prognostic influence is also emerging as recent data suggest that any monosomy in a complex karyotype (≥3 abnormalities) may have the same poor prognostic impact as monosomy 5 and 7 (−5,−7). Objectives: Thus, the principal goal of the present study was to test whether a MK further worsen the already poor prognostic influence of a complex karyotype and to establish whether autosomal monosomies have the same unfavourable prognostic impact on OS and progression free interval (PFI) as −5/−7. Methods: The eighty-five consecutive MDS patients with a complex karyotype analysed by the present study were included in a series of 631 patients who came at our observation in the period January 2000-December 2010. They were thirty-two females and fifty-three males with a median age of 65 years (range 25–85). Fifty-five patients were diagnosed as MDS and were subdivided in 3 RARS, 6 RA, 6 RCMD, 2 RCMDS, one MDS-u, 13 RAEB-1 and 24 RAEB-2. The IPSS score was intermediate-1 in 5, intermediate-2 in 23 and high in 27. During the follow-up 31 MDS patients died and 41 experienced disease progression (3 RARS, 5 RA, 4 RCMD, one MDS-u, 9 RAEB-1 and 19 RAEB-2). Thirty patients were diagnosed as AML evolved from MDS. Fifteen of them received supportive treatment only, the remaining single agent chemotherapy to control leukocytosis. Nineteen of these thirty patients died of disease related complications. Results: On conventional cytogenetics 37 patients (4 RA, 5 RCMD, one MDS-u, 8 RAEB-1, 12 RAEB-2 and 7 AML) presented a complex karyotype without monosomies and 48 (3 RARS, 2 RA, 2 RCMDS, one RCMD, 5 RAEB-1, 12 RAEB-2, 24 AML) a complex karyotype with monosomies. These two patients subgroups were comparable in terms of age, sex distribution, haemoglobin level, leukocyte or platelet counts, bone marrow blast cell percentage and IPSS score. However, median survival was 8 months (range 1–131) for patients with a complex karyotype without monosomies and 5 months (range 1–81) for those with a complex karyotype with monosomies (p=0.001). Twenty patients (54.0%) without monosomies died after a median time of 6 months (range 2–35), whereas 30 patients (62.5%) with monosomies died after a median time of 5 months (range 1–24). Disease progression was observed in 22 (59.4%) and 19 (39.5%) patients respectively (p=0.001). The 48 patients with a MK were further subdivided in those with −5/−7 versus those with other autosomal monosomies. The 23 patients with −5/−7 presented a median survival of 4 months (range 1–15) and the 25 with other monosomies presented a median survival of 5 months (range 1–81) (p=Not Significant). Fourteen −5/−7 patients died after a median time of 4 months (range 1–15) and 13 patients with autosomal monosomies died after a median time of 6 months (range 1–24). Disease progression occurred in 12 (52.1%) and 7 (28%) respectively. Conclusions: i) a MK further refines the prognostic stratification of MDS with a complex karyotype as it identifies a subgroup of patients with an extremely poor clinical outcome; ii) autosomal monosomies have an impact on disease outcome as detrimental as −5/−7. Disclosures: No relevant conflicts of interest to declare.

scholarly journals CAR-NK Cells in the Treatment of Solid Tumors

2021 ◽  
Vol 22 (11) ◽  
pp. 5899
Author(s):  
Ewa Wrona ◽  
Maciej Borowiec ◽  
Piotr Potemski
Keyword(s):  
Nk Cells ◽  
Solid Tumors ◽  
Hematological Malignancies ◽  
Toxicity Profile ◽  
Multiple Sources ◽  
Eligibility Criteria ◽  
Hematological Neoplasms ◽  
Current State ◽  
Car T ◽  
The Cost

CAR-T (chimeric antigen receptor T) cells have emerged as a milestone in the treatment of patients with refractory B-cell neoplasms. However, despite having unprecedented efficacy against hematological malignancies, the treatment is far from flawless. Its greatest drawbacks arise from a challenging and expensive production process, strict patient eligibility criteria and serious toxicity profile. One possible solution, supported by robust research, is the replacement of T lymphocytes with NK cells for CAR expression. NK cells seem to be an attractive vehicle for CAR expression as they can be derived from multiple sources and safely infused regardless of donor–patient matching, which greatly reduces the cost of the treatment. CAR-NK cells are known to be effective against hematological malignancies, and a growing number of preclinical findings indicate that they have activity against non-hematological neoplasms. Here, we present a thorough overview of the current state of knowledge regarding the use of CAR-NK cells in treating various solid tumors.

scholarly journals Next Generation Cytogenetics in Myeloid Hematological Neoplasms: Detection of CNVs and Translocations

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 3001
Author(s):  
María Chicano ◽  
Diego Carbonell ◽  
Julia Suárez-González ◽  
Sergio Lois ◽  
Mercedes Ballesteros-Culebras ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Lymphoblastic Leukemia ◽  
Copy Number Variations ◽  
Next Generation ◽  
Trisomy 8 ◽  
Chromosomal Alterations ◽  
Hematological Neoplasms ◽  
Myeloid Neoplasm ◽  
Myeloid Neoplasms ◽  
Conventional Cytogenetics

Conventional cytogenetics are the gold standard for the identification of chromosomal alterations recurrent in myeloid neoplasms. Some next-generation sequencing (NGS) panels are designed for the detection of copy number variations (CNV) or translocations; however, their use is far from being widespread. Here we report on the results of a commercial panel including frequent mutations, CNVs and translocations in myeloid neoplasms. Frequent chromosomal alterations were analyzed by NGS in 135 patients with myeloid neoplasms and three with acute lymphoblastic leukemia. NGS analysis was performed using the enrichment-capture Myeloid Neoplasm-GeneSGKit (Sistemas Genómicos, Spain) gene panel including 35 genes for mutational analysis and frequent CNVs and translocations. NGS results were validated with cytogenetics and/or MLPA when possible. A total of 66 frequent alterations included in NGS panel were detected, 48 of them detected by NGS and cytogenetics. Ten of them were observed only by cytogenetics (mainly trisomy 8), and another eight only by NGS (mainly deletion of 12p). Aside from this, 38 secondary CNVs were detected in any of the genes included mainly for mutational analysis. NGS represents a reliable complementary source of information for the analysis of CNVs and translocations. Moreover, NGS could be a useful tool for the detection of alterations not observed by conventional cytogenetics.

The BMP/BMPR/Smad pathway directs expression of the erythroid-specific EKLF and GATA1 transcription factors during embryoid body differentiation in serum-free media

Development ◽  
2002 ◽  
Vol 129 (2) ◽  
pp. 539-549 ◽  
Author(s):  
Carrie A. Adelman ◽  
Subrata Chattopadhyay ◽  
James J. Bieker
Keyword(s):  
Embryoid Body ◽  
Es Cells ◽  
Expression Patterns ◽  
Embryonic Stem ◽  
Dominant Negative ◽  
Erythroid Cell ◽  
Specific Gene ◽  
Smad Pathway ◽  
Cellular Expression ◽  
Novel Approach

Erythroid cell-specific gene regulation during terminal differentiation is controlled by transcriptional regulators, such as EKLF and GATA1, that themselves exhibit tissue-restricted expression patterns. Their early expression, already in evidence within multipotential hematopoietic cell lines, has made it difficult to determine what extracellular effectors and transduction mechanisms might be directing the onset of their own transcription during embryogenesis. To circumvent this problem, we have taken the novel approach of investigating whether the ability of embryonic stem (ES) cells to mimic early developmental patterns of cellular expression during embryoid body (EB) differentiation can address this issue. We first established conditions whereby EBs could form efficiently in the absence of serum. Surprisingly, in addition to mesoderm, these cells expressed hemangioblast and hematopoietic markers. However, they did not express the committed erythroid markers EKLF and GATA1, nor the terminally differentiated β-like globin markers. Using this system, we determined that EB differentiation in BMP4 was necessary and sufficient to recover EKLF and GATA1 expression and could be further stimulated by the inclusion of VEGF, SCF, erythropoietin and thyroid hormone. EBs were competent to respond to BMP4 only until day 4 of differentiation, which coincides with the normal onset of EKLF expression. The direct involvement of the BMP/Smad pathway in this induction process was further verified by showing that erythroid expression of a dominant negative BMP1B receptor or of the inhibitory Smad6 protein prevented induction of EKLF or GATA1 even in the presence of serum. Although Smad1, Smad5 and Smad8 are all expressed in the EBs, BMP4 induction of EKLF and GATA1 transcription is not immediate. These data implicate the BMP/Smad induction system as being a crucial pathway to direct the onset of EKLF and GATA1 expression during hematopoietic differentiation and demonstrate that EB differentiation can be manipulated to study induction of specific genes that are expressed early within a lineage.

scholarly journals Report of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Infection in Four Patients with Hematological Malignancies Treated at King Fahad Medical City, Riyadh, Saudi Arabia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4903-4903 ◽  
Author(s):  
Ibraheem H Motabi ◽  
Syed Ziauddin A. Zaidi ◽  
Mamoun Hassan Ibrahim ◽  
Imran K Tailor ◽  
Nawal Faiez Alshehry ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Middle East ◽  
Supportive Care ◽  
Hematological Malignancies ◽  
Conflicts Of Interest ◽  
Lower Lobe ◽  
Middle East Respiratory Syndrome ◽  
Rt Pcr ◽  
Peak Period ◽  
Increased Risk

Abstract Introduction Respiratory viruses are an important cause of outbreaks of pneumonia in hematological malignancy patients. Recently, novel Middle East respiratory syndrome coronavirus (MERS-CoV) caused a cluster of life-threatening infections in Saudi Arabia (688 confirmed MERS-CoV infection cases with 282 deaths were reported to WHO by June 6, 2014 including 28% cases in HCW). Most patients had upper &/or lower respiratory tract symptoms but other features included abdominal pain, diarrhea, acute kidney injury & shock. Few hematology units were closed due to havoc. Here we report clinical features & outcome of 4 patients diagnosed at our unit during the peak period (mid-March through May 2015) including 2 who got chemotherapy (chemo) soon after recovery. Patient #1 A 62-yr-old male had free λ light chain multiple myeloma (MM) with spinal cord compression. After surgery & local radiation, he was sent to us with paraplegia & grade 4 infected sacral bedsore that needed inpatient care. He was started on CyBorD Cycle 2 on April 24, 2014. On May 2, he had a fever spike with shortness of breath (SOB) & cough. He was started on antibiotics. CXR revealed bilateral infiltrates & right sided pleural effusion. His O2 sat dropped & he needed CPAP. Oseltamivir was started & sputum was positive for MERS-CoV RT-PCR. He became afebrile with decreasing O2 requirement, CXR normalized & RT-PCR for MERS-CoV turned negative. Later he was able to receive 3rdcycle of CyBorD. Patient #2 A 65-yr-old lady came to us with B symptoms & huge organomegaly due to stage-IV DLBCL. On May 2, 2014 RCVP chemo was started. On day 6, she spiked fever with SOB, cough & was started on imipenem. CXR showed consolidation in right lower lobe. She needed 4L of O2/min. On May 10, 2014, she worsened with RR 32/min, O2 sat 79% on 15L O2/min & BP 79/47 mmHg. CXR revealed bilateral consolidation. She needed intubation & inotropic support in ICU. Vancomycin & oseltamivir were started & RT-PCR was positive for MERS-CoV on two nasopharyngeal swabs (NPS). LFT & RFT were normal but she continued to decline & died on May 13, 2014. Patient # 3 A 22-yr-old lady with past H/O AML t(8;21) was admitted on April 27, 2014 with 3 day H/O cough, fever & SOB. CXR had infiltrates in left lower lobe. She had severe pancytopenia & BMB confirmed relapsed AML. She had slightly raised LFT. Urine grew Ent. fecium. Antibiotics & voriconazole were used. She remained febrile over next 2 days. CT chest revealed extensive bilateral consolidation. She needed O2 up to 5L/Min for few days. RT-PCR for MERS-CoV was positive from NPS. She was initiated on oseltamivir. She became afebrile after 2 days & repeated RT-PCR for MERS-CoV was negative. Fludara, Ara-C (FA) chemo was started. She remained neutropenic for next 4 weeks but there was no recurrence of respiratory symptoms. BMB on day 28 of FA confirmed CR. CT chest revealed complete resolution of air space opacities. She was discharged with plan to undergo matched sibling donor Allo-HSCT. Patient #4 A 76-yr-old male with H/O HTN & CKD was diagnosed to have IgA κ MM. He was started on MPV chemo as inpatient due to logistic reasons. After 3 cycles of MPV, serum free κ chains decreased by 91% but remained on dialysis. On 21 April, 2014 he developed cough, SOB & fever. CXR revealed bilateral infiltrates & antibiotics were started. He worsened over next few days & CXR showed worsening bilateral consolidation. Eventually he needed intubation. He was treated with antimicrobials including voriconazole & oseltamir. RT-PCR for MERS-CoV was positive from NPS. Unfortunately he died few days later. Discussion: Patients with hematological malignancies are at increased risk of community & hospital-acquired infections. Recent outbreak of MERS-CoV infection has created a havoc among hematologists community. There is uncertainty about impact of MERS-CoV infection on continuation of chemo. We report 4 cases of hematological malignancies with MERS-CoV infection. Three of the 4 patients developed severe pneumonia & required intubation (2 died later) & one had milder form of pneumonia treated in isolation room. In addition to supportive care, all 4 received antimicrobials & oseltamivir. Chemo was safe soon after recovery from infection in the surviving 2 patients. We propose that during MERS-CoV epidemics, pneumonia can be treated with supportive care, antibiotics & oseltamivir. Chemo can be continued for the malignant disease soon after recovery. Further reports are needed to confirm our findings. Disclosures No relevant conflicts of interest to declare.

Cis and trans control of erythroid cell-specific gene expression during erythropoiesis

1988 ◽  
Vol 1988 (Supplement 10) ◽  
pp. 145-155
Author(s):  
P. R. HARRISON ◽  
M. PLUMB ◽  
J. FRAMPTON ◽  
I. CHAMBERS ◽  
D. LLEWELLYN ◽  
...  
Keyword(s):  
Gene Expression ◽  
Erythroid Cell ◽  
Specific Gene ◽  
Specific Gene Expression ◽  
Cis And Trans

Chromosomal Abnormalities in MDS Are Linked to Dysregulation of CDC20 and CEP55 Genes

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 36-37
Author(s):  
Mayara Magna de Lima Melo ◽  
Daniela de Paula Borges ◽  
Antônio Wesley Araújo Dos Santos ◽  
Gabrielle Melo Cavalcante ◽  
Leticia Rodrigues Sampaio ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Chromosomal Instability ◽  
Spindle Assembly Checkpoint ◽  
Chromosomal Abnormalities ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Normal Karyotype ◽  
Mitotic Arrest ◽  
Complex Karyotype ◽  
Increased Risk

Myelodysplastic syndrome (MDS) is a clonal hematopoietic disorder characterized by cytopenias and an increased risk of progression to acute myeloid leukemia (AML). Its pathogenesis is strictly linked to chromosomal instability, which in turn provides a valuable prognostic marker. Malignant cells develop alternative routes to escape mitosis checkpoints, overcoming the mitotic arrest imposed by Spindle Assembly Checkpoint (SAC), a process dependent on CDC20 inactivation. Abnormal levels of CDC20 can inhibit mitotic arrest, promoting premature exit from mitosis. Overexpression of CEP55 also facilitates the mitotic exit, resulting in polyploidy (an event called Mitotic Slippage). Since chromosomal abnormalities are one of the most important prognostic factors for patients with MDS, this study aimed to analyze the possible link between chromosomal abnormalities and CDC20 and CEP55 mRNA expression in MDS. We evaluated the bone marrow cells from 45 patients diagnosed as MDS according to 2016 WHO-classification (1 MDS-SLD, 15 MDS-RS-MLD, 5 MDS-MLD, 1 t-MDS, and 23 MDS-EB) and 5 bone marrow of healthy controls. Conventional Karyotyping was performed by G-banding of 20 metaphases whenever possible. TaqMan expression assays for CDC20 (Hs00426680_mH) and CEP55 (Hs01070181_m1) were performed in duplicate and the expression ratios were calculated using the 2−ΔCq method. Normality was evaluated by Shapiro-Wilk test. Outliers were removed. The Student's t-test or one-way ANOVA with Tukey/Games Howell post-hoc test was used to analyze the influence of relative expression regarding variables. Patients with MDS showed increased expression of CDC20 and CEP55 compared to healthy individuals (p<0.0001 and p<0.0001). Regarding karyotype, there was the overexpression of CDC20 and CEP55 in patients with altered karyotype and aneuploid karyotype when compared to patients with normal karyotype (p <0.0001 and p =0.001; p = 0.013 and p = 0.022, respectively) (Figure 1A-D). CDC20 and CEP55 have fundamental functions in controlling the progression of metaphase to anaphase and both, when upregulated, induce chromosomal instability. Additionally, patients with del(7q) and complex karyotype showed hyperexpression of CEP55 when compared with patients with normal karyotype (p = 0.005 and p = 0.019) (Figure 1E-F), while patients with deletion (5q) had an increased expression of CDC20 when compared with patients with normal karyotype (p <0.0001). Our group previously demonstrate that high CDC20 protein expression is associated with complex karyotype in MDS patients. Thus, we hypothesized that the deregulation of CDC20 and CEP55 expression induces chromosomal changes, each one in its way. Both can cause disturbances in crucial phases of mitosis (anaphase and cytokinesis, respectively). Finally, we detected a strong correlation between CDC20 and CEP55 (r = 0.646; p <0.0001), suggesting both genes may play a synergistic role during chromosomal abnormalities in MDS, creating possible new targets to be evaluated in MDS. Our data suggest CDC20 and CEP55 as possible new therapeutic targets in MDS. There is a need for further studies, validations and urgent in-depth investigations in cell lines/primary samples or murine models. Disclosures No relevant conflicts of interest to declare.

A Complex Karyotype but Not Monosomy 7 Is an Independent Prognostic Factor in Advanced Childhood MDS.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2452-2452
Author(s):  
Gudrun Gohring ◽  
Kyra Michalova ◽  
Berna Beverloo ◽  
David Betts ◽  
Jochen Harbott ◽  
...  
Keyword(s):  
Chromosome Aberrations ◽  
Conflicts Of Interest ◽  
Bone Marrow Failure ◽  
Prognostic Significance ◽  
Complex Karyotype ◽  
Similar Frequency ◽  
Hematopoietic Stem ◽  
Monosomy 7 ◽  
Significant Difference ◽  
Secondary Mds

Abstract Disclosure: No relevant conflicts of interest to declare. To study the clinical significance of recurrent chromosome aberrations in childhood MDS, cytogenetic data of 394 consecutive children with refractory cytopenia (RC) (N=215), RAEB (N=141) and RAEB-T (N=38) analyzed in the regional cytogenetic reference centers and registered in the prospective study EWOG-MDS 98 between 1998 and 2005 were evaluated. At diagnosis, a karyotype could be defined in 279/394 patients (pts) (71%). No karyotype was obtained in 16% of pts with RC compared to 8% pts with RAEB and RAEB-t (p<0.001). Clonal chromosome aberrations were more common in pts with advanced MDS (RAEB and RAEB-T, 61%) compared to RC (29%), and in pts with secondary (69%) compared to primary MDS (36%) (p<0.001). Monosomy 7 was the most frequent aberration occurring with similar frequency in RC (47% of abnormal karyotypes) compared to advanced MDS (49%) and in primary (53%) compared to secondary (41%) MDS. In addition, aberrations typical for de novo AML such as aberrations involving 11q23 or 3q, t(6;9) and del(9q) were noted in morphologically and clinically unequivocal MDS cases. Recurrent aberrations of adult MDS like isolated del(5q), del(20q) and -Y were very uncommon indicating a different pathogenesis of these cases. In pts with advanced MDS, there was no significant difference in overall survival (OS) of pts with normal karyotype (44% ± 18) compared to pts with monosomy 7 (58% ± 19) and patients with other karyotypes (61% ± 22). However, pts with advanced MDS and a complex karyotype (defined by ≥ 3 chromosome aberrations, presence of structural aberrations and excluding clonal evolution of monosomy 7) had a shorter OS (16% ±15, p<0.01). OS and event-free survival after hematopoietic stem cell transplantation (HSCT) in pts with complex karyotypes was inferior compared to that of pts with other cytogenetic aberrations (p=0.012 and 0.039, respectively). Within the group of pts with secondary MDS, complex karyotypes were found in MDS evolving from inherited bone marrow failure disorders or after radio-/ chemotherapy, but absent in familial MDS and cases evolving from acquired aplastic anemia. As shown in a multivariate Cox analysis, advanced MDS, secondary MDS, the presence of a complex karyotype and HSCT were identified as independent prognostic factors for OS. Thus, this study demonstrates the prognostic significance of cytogenetic findings in advanced childhood MDS independent of HSCT.

Klf1 Regulatory Networks in Primary Erythroid Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1462-1462
Author(s):  
Michael Tallack ◽  
Thomas Whitington ◽  
Brooke Gardiner ◽  
Eleanor Wainwright ◽  
Janelle Keys ◽  
...  
Keyword(s):  
Regulatory Networks ◽  
Conflicts Of Interest ◽  
Fetal Liver ◽  
Es Cells ◽  
Erythroid Differentiation ◽  
Erythroid Cell ◽  
Gene Promoters ◽  
Erythroid Cells ◽  
Red Cell Membrane ◽  
Sequencing Platform

Abstract Abstract 1462 Poster Board I-485 Klf1/Eklf regulates a diverse suite of genes to direct erythroid cell differentiation from bi-potent progenitors. To determine the local cis-regulatory contexts and transcription factor networks in which Klf1 works, we performed Klf1 ChIP-seq using the SOLiD deep sequencing platform. We mapped more than 10 million unique 35mer tags and found ∼1500 sites in the genome of primary fetal liver erythroid cells are occupied by endogenous Klf1. Many reside within well characterised erythroid gene promoters (e.g. b-globin) or enhancers (e.g. E2f2 intron 1), but some are >100kb from any known gene. We tested a number of Klf1 bound promoter and intragenic sites for activity in erythroid cell lines and zebrafish. Our data suggests Klf1 directly regulates most aspects of terminal erythroid differentiation including synthesis of the hemoglobin tetramer, construction of a deformable red cell membrane and cytoskeleton, bimodal regulation of proliferation, and co-ordination of anti-apoptosis and enucleation pathways. Additionally, we suggest new mechanisms for Klf1 co-operation with other transcription factors such as those of the gata, ets and myb families based on over-representation and spatial constraints of their binding motifs in the vicinity of Klf1-bound promoters and enhancers. Finally, we have identified a group of ∼100 Klf1-occupied sites in fetal liver which overlap with Klf4-occupied sites in ES cells defined by Klf4 ChIP-seq. These sites are associated with genes controlling the cell cycle and proliferation and are Klf4-dependent in skin, gut and ES cells, suggesting a global paradigm for Klfs as regulators of differentiation in many, if not all, cell types. Disclosures No relevant conflicts of interest to declare.

Impact of TET2 mutations On Responsiveness to Demethylating Agents in MDS.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1606-1606
Author(s):  
Anna M. Jankowska ◽  
Mohammed Shaik ◽  
Heather Cazzolli ◽  
Rebecca Ganetzky ◽  
Mikkael A. Sekeres ◽  
...  
Keyword(s):  
Conflicts Of Interest ◽  
Methylation Status ◽  
Epigenetic Silencing ◽  
Specific Gene ◽  
Aberrant Methylation ◽  
Global Methylation ◽  
Myeloid Malignancies ◽  
Demethylating Agents ◽  
Potential Marker ◽  
Epigenetic Instability

Abstract Abstract 1606 Poster Board I-632 Aberrant epigenetic silencing of tumor suppressor and differentiation genes constitutes an important mechanism in the pathogenesis of MDS and related myeloid malignancies. Demethylationg agents such as azacitidine and decitabine lead to degradation of DNMT1 and may reverse aberrant methylation. While the drugs demonstrate efficacy in MDS, response rates are variable. Thus, many primarily refractory patients are exposed to these therapies unnecessarily. While search for markers of responsiveness included study of methylation status of potential marker promoters or global methylation patterns, to date predictive tests have not been developed. Similarly, mechanisms of epigenetic instability responsible for wide-spread promoter methylation have not been clarified, preventing development of diagnostic markers. TET2 mutations are frequent events in a variety of MDS subtypes, particular chronic myelomonocytic leukemia (CMML) and other MDS/MPN, as well as AML derived from those conditions. It is likely that TET2 alterations are important in the pathogenesis of myeloid malignancies, but little is known regarding the function of TET2. A recent report indicated that a related family member, TET1, converts 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (hmC). Hydroxylation of 5mC prevents DNMT1 from homologous methylation of daughter DNA strands during cell division, thus preventing maintenance methylation (Tahiliani et al. Nature 324, 2009). Consequently, closely related TET2 may play a role in epigenetic regulation. As a consequence, TET2 mutations may lead to accumulation of aberrantly methylated CpG islands. Of utmost importance is whether TET2 mutations or resultant epigenetic silencing of specific gene or gene groups affects response to hypomethylating agents. We hypothesized that TET2 mutations play a role in epigenetic instability and may serve as markers of responsiveness/refractoriness to the therapy with demethylating agents. We have determined TET2 mutational status by sequencing all exons in 32 patients with myeloid malignancies (MDS (N=18) and MDS/MPN (N=14)) who underwent therapy with the demethylating agents azacitidine (N=27) or decitabine (N=5). For definition of response we applied International Working Group Criteria in patients who received a sufficient dose and number of cycles to allow assessment of response. Overall response rate (complete+partial responses (CR+PR) + hematologic improvement (HI)) was achieved for 9/32 patients (28%) after 35 cycles, including 4 patients who achieved CR, 2 PR, and 3 CI. In total, 12 TET2 mutations were identified in 9/32 patients (28%), of whom 5 had MDS/MPN (3 with CMML-1/2) and 4 had sAML. Unique compound heterozygosity was found in 3 patients; consequently biallelic inactivation of TET2 was found in 4 patients. For analyses, patients with partial and complete responses were compared with refractory patients and response was correlated with the presence of TET2 mutations. Among TET2-mutated patients, only 1 patient responded to therapy, whereas 8 additional patients, including 3 patients with biallelic inactivation of the TET2 gene, did not show any improvement (11%). In contrast, among patients with WT TET2 gene, responses were seen in 8/23 patients (35%; p=.19). While the cohort of treated patients was small, our preliminary results indicate that the presence of TET2 mutations may represent a negative predictor of response to demethylating agents. Disclosures No relevant conflicts of interest to declare.

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