scholarly journals Clinico-Genomic Profiling and Clonal Dynamic Modeling of Spliceosome-Mutant Myelodysplastic Syndrome and Acute Myeloid Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 23-23
Author(s):  
Disha Dalela ◽  
Shyam A. Patel ◽  
Jonathan Gerber ◽  
Karl Simin ◽  
Qiming Shi
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Dynamic Modeling ◽  
Rna Splicing ◽  
Myeloid Leukemia ◽  
Splicing Factor ◽  
Wbc Count ◽  
Clonal Dynamic ◽  
Acute Myeloid

Introduction: The identification of driver mutations has dramatically changed the management of myeloid malignancies. More recently, mutations have been identified in RNA splicing machinery in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) (Yoshida et al. 2011). Recurring missense mutations have been observed in the RNA splicing factor 3B subunit 1 (SF3B1), serine and arginine-rich splicing factor (SRSF2) and U2 small nuclear RNA auxiliary factor 1 (U2AF1). In this study, we sought to decipher the disease-specific features and clinical outcomes of individual spliceosome mutations in patients with MDS and AML. Methods: We conducted a retrospective observational study of 40 patients with one or more mutations in 3 spliceosome genes (SRSF2, U2AF1, SF3B1) from the University of Massachusetts (UMass) Leukemia Registry. Demographics, peripheral blood data, clinical parameters such as treatment offered including bone marrow transplant and response to chemotherapy was longitudinally recorded. We performed clonal dynamic modeling to identify clonal evolution in individual patients with spliceosome-mutant MDS or AML. Results: Longitudinal data was available for 83% (33/40) patients with an average follow up duration of 91 weeks. Average age at diagnosis was 75±4 years which was consistent across the 3 mutational cohorts. A mortality of ~35% was observed in our cohort (Table 2). MDS was diagnosed in 48% (19/40), AML and AML-MRC were diagnosed in 33% (13/40) and 13% (5/40), respectively (Table 1). SRSF2 was the most common spliceosome mutation (50%) and SF3B1 and U2AF1 were equally divided in the remainder. Cytogenetic abnormalities were found in 5/33 (15%) in SRSF2, 4/33 (12%) in U2AF1, and 1/33 (3%) in the SF3B1 groups. Of the 16 patients with SRSF2-mutant hematological conditions, 7/16 (40%) had persistent disease (PD) which was similar across the other two spliceosome genes. Compared to U2AF1- and SF3B1-mutant patients, SRSF2-mutant patients presented with a higher WBC count (mean 45.9 x 103/mcl ± 13.6 x 103/mcl), higher bone marrow (BM) cellularity (73% ± 4.4%), and higher BM blast percentage (24% ± 6.9%) at the time of diagnosis (Table 3), which was independent of the FLT3 status. The most commonly recurring co-occurring mutants with SRSF2 were TET2 (occurred 8/16 times along with SRSF2 with a rate of 50%), IDH2 (31%), STAG2 (25%) and RUNX1 (25%). In the U2AF1-mutant cohort, RUNX1 (30%) and TET2 (20%) were the most frequent co-mutants. In the SF3B1 cohort, BCOR (29%) and KRAS (29%) were the most frequently mutated and shared few co-occurring mutations with SFSR2-mutant and U2AF1-mutant cohorts as demonstrated in the circosplots (Figure 3). The heatmap further elaborates this association and alludes to a possible genetic signature associated with favorable or adverse clinical outcomes (Figure 2). Conclusion: This study deciphers among SRSF2-, U2AF1-, and SF3B1-mutant MDS/AML and demonstrates that SRSF2-mutant MDS/AML presents with higher WBC count, BM cellularity, and BM blast burden. SRSF2-mutant MDS/AML carries the most dismal prognosis amongst the spliceosome mutations. The co-mutational landscape of SF3B1-mutant MDS/AML is distinctly different from SRSF2 and U2AF1 cohort. While we only identified 1 individual with SF3B1 mutation with longitudinal data and hence no meaningful conclusion is possible, SRSF2 cohort shows poor response to standard chemotherapy in 2/3 individuals (Figure 1). We also found that BRAF and CEBPA are not co-occurring mutations within the spliceosome-mutant cohort, suggesting mutual exclusivity (Figure 2). While our understanding of MDS/AML expands, new drugs are constantly under development and have led to significant improvements in the disease outcome in younger patients. Seiler et al recently studied a new oral drug H3B-8800, which binds the SF3B complex in a competitive manner and has demonstrated potent inhibition and lethality of the spliceosome-mutant cells (Seiler et al. 2018). After demonstration of survival advantage in vivo in murine models, the drug is now in Phase 1 clinical trial which is pending completion soon. Our dataset provides clinical correlates of spliceosome-mutant AML/MDS in a longitudinal fashion and also alludes to a possible genetic signature associated with favorable or adverse outcomes in these patients. Disclosures No relevant conflicts of interest to declare.

NUP98-HOXD13 Transgenic Mice Develop Myelodysplastic Syndrome, Acute Myeloid Leukemia, and Pre-T Lymphoblastic Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 345-345
Author(s):  
Yingwei Lin ◽  
Christopher Slape ◽  
Zhenhua Zhang ◽  
Peter D. Aplan
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Transgenic Mice ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Lymphoblastic Leukemia ◽  
Gene Rearrangements ◽  
Hematologic Disease ◽  
Amino Terminal ◽  
Acute Myeloid

Abstract The NUP98 gene is located at chromosome 11p15 and encodes the 98 kd component of the nuclear pore complex; this protein normally functions as a docking protein involved in nucleocytoplasmic transport. NUP98 is fused to at least 15 different partner genes by chromosomal translocation in a wide spectrum of hematological malignancies including acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myelogenous leukemia (CML), and pre-T lymphoblastic leukemia (pre-T LBL). Over half of the known NUP98 gene fusions involve fusions to a HOX family member; these fusions invariably retain the amino terminal FG repeats of NUP98 and the homeodomain DNA-binding region of the HOX partner. The NUP98-HOXD13 fusion was initially identified in a patient with MDS that subsequently transformed to erythroleukemia, and has subsequently been identified in AML M1 and M2 patients as well. To model this disease in vivo, we generated transgenic mice which expressed the NUP98-HOXD13 (NHD13) fusion from vav regulatory elements. The NHD13 transgene is ubiquitously expressed in hematopoietic tissues such as thymus, spleen, and bone marrow, and is not expressed in other tissues. Serial CBCs from clinically healthy mice aged 4–7 months demonstrated a progressive neutropenia, lymphopenia, anemia, and macrocytosis. Peripheral blood smears showed signs of dysplasia including giant platelets and hypersegmented neutrophils; bone marrow exam showed an increase number of dysplastic binucleate erythroblasts and increased apoptosis, consistent with a diagnosis of MDS. 10/10 (100%) of the NHD13 mice died of hematologic disease by 14 months of age; in contrast, none of the non-transgenic control littermates developed evidence of hematologic disease. We classified the hematologic diseases according to the Bethesda proposals. Three mice died with MDS, two mice had pre-T LBL, two had acute undifferentiated leukemia, one had megakaryocytic leukemia, one had myeloid leukemia with maturation, and one had both pre-T LBL and erythroid leukemia. The malignant blasts from mice with pre-T LBL showed monoclonal T-cell receptor B gene rearrangements and were positive for CD3, 4, and 8. The mouse with megakaryocytic leukemia had serial CBCs documenting a platelet count of 3.2 million/uL, rising to >15million/uL at the time of death. This mouse had CD41+ megakaryocytes and megakaryoblasts invading the liver and spleen, and an osteosclerotic bone marrow reminiscent of chronic idiopathic myelofibrosis (CIMF). The mouse with concurrent pre-T LBL and erythroid leukemia had replacement of the thymus and infiltration of the lung with T-lymphoblasts which had a clonal TCRB gene rearrangement; interestingly, the spleen, liver, and bone marrow of this mouse were invaded with erythroblasts that were negative for CD3 and TCRB gene rearrangements. We conclude that the NHD13 transgene consistently induces an MDS, of variable severity, in these mice. Some mice die of severe anemia due to MDS, and MDS transforms into an acute non-lymphoid leukemia in other mice. Still other mice die of pre-T LBL which we believe evolves in the thymus separately from the MDS. These data demonstrate that the NHD13 fusion gene is transforming in both lymphoid and myeloid cells.

Clinical Significance of Free Circulating CD33 in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4502-4502 ◽  
Author(s):  
Menna Hodge ◽  
Francis Giles ◽  
Adam Abdool ◽  
Susan O’Brien ◽  
Michael Keating ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Gemtuzumab Ozogamicin ◽  
Leukemic Cells ◽  
Clinical Behavior ◽  
Cytogenetic Abnormalities ◽  
Cytotoxic Compound ◽  
Wbc Count ◽  
Acute Myeloid

Abstract CD33, a 67-kDa sialoglycoprotein expressed on the cell surface of monocytic/myeloid lineage and early hematopoietic progenitor cells, is frequently expressed in patients with acute myeloid leukemia (AML). Gemtuzumab ozogamicin (GO), an immunoconjugate consisting of a humanized anti-CD33 antibody and a cytotoxic compound (N-acetyl-γ-calicheamicin dimethylhydrazine), targets CD33 and has shown promising results in patients with AML. No evidence of a relationship between the levels of CD33-positive leukemic cells and clinical response has been found. We investigated the possibility that cell-free circulating CD33 (cCD33) might be useful as a marker of clinical behavior. We used a newly developed bead-based immunoassay to measure cCD33 in the plasma of patients with AML (n = 97) or myelodysplastic syndrome (MDS; n = 44). All patients were treated with standard therapy including idarubicin and ara-C. cCD33 levels were significantly higher in patients with MDS (median, 1600 U/μL; range, 102–791,350 U/μL) than in those with AML (median, 2709 U/μL; range: 62–263,349 U/μL) (P = 0.004). High-risk cytogenetic abnormalities were associated with higher cCD33 levels in patients with MDS (P = 0.04) but not in patients with AML (P = 0.72). cCD33 levels correlated with WBC count and % monocytes in patients with AML (R >0.35) but not in patients with MDS. cCD33 levels correlated with clinical behavior only among AML patients with intermediate-risk cytogenetic abnormalities (n = 56); those with cCD33 levels above the median had longer survival (P = 0.04). These data confirm the presence of cCD33 in AML and MDS and also suggest that cCD33 can be used as a tumor marker in patients with AML. Although further study is needed for confirmation, cCD33 appears to result from turnover of leukemic cells, may play a role in patients being treated with GO, and should be considered in the pharmacokinetic and pharmacodynamic studies of such therapy. cCD33 in AML patient with intermediate cytogenetic abnormalities cCD33 in AML patient with intermediate cytogenetic abnormalities

Clinical Significance of Free Circulating CD34 in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4495-4495
Author(s):  
Menna Hodge ◽  
Francis Giles ◽  
Adam Abdool ◽  
Susan O’Brien ◽  
Michael Keating ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Performance Status ◽  
Signal Transduction Pathway ◽  
Leukemic Cells ◽  
Neural Cells ◽  
And Performance ◽  
Wbc Count ◽  
Acute Myeloid

Abstract CD34 is an approximately 116-kd glycophosphoprotein expressed in hematopoietic progenitor cells, endothelial cells, and some mesenchymal and neural cells. CD34 is a typical adhesion molecule capable of inducing the cell signal transduction pathway leading to adhesion and differentiation. We used a newly developed bead-based assay to measure cell-free circulating CD34 (cCD34) in the plasma of patients with acute myeloid leukemia (AML; n = 98) and myelodysplastic syndrome (MDS; n = 50). Levels of cCD34 were significantly higher in AML (median 10983, range: 844–100,4191 U/10 μl than in MDS (median: 8749, range:102–791,350 U/10 μl) patients (P<0.01). cCD34 levels were higher among patients with high-risk cytogenetic abnormalities in AML (P = 0.01) but not MDS (P = 0.92). When grouped together, AML and MDS patients with cCD34 levels higher than the median (10,845 U/μl) had significantly shorter survival than those with lower levels (P = 0.01). This association was independent of cytogenetic grouping, age, and performance status. cCD34 levels did not correlate with percent of blasts or CD34+ cells but did correlate with WBC count (R = 0.36) in patients with AML, suggesting that cCD34 reflects the overall leukemia load. Although further study is needed for confirmation, cCD34 appears to result from turnover of leukemic cells and may affect the activation of certain pathways, therefore influencing survival and clinical outcome. Figure Figure

Flt3 Receptor Inhibition Abolishes Constitutive NFκB Activation in High-Risk Myelodysplastic Syndrome and Acute Myeloid Leukemia.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2434-2434
Author(s):  
Jennifer Grosjean ◽  
Lionel Ades ◽  
Simone Bohrer ◽  
Pierre Fenaux ◽  
Guido Kroemer
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Plasma Membrane ◽  
High Risk ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Bone Marrow Cells ◽  
Constitutive Activation ◽  
Nf Kappab ◽  
Acute Myeloid

Abstract High-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are characterized by the constitutive activation of the anti-apoptotic transcription factor NF-kappaB, via the activation of the IKK complex. We show that constitutive activation of the receptor tyrosine kinase Flt3 is responsible for IKK activation and this activation of the NF-kappaB pathway was found to involve a not yet described phosphorylation of the IKK and IkBa complex involving tyrosine residues compared to serine residues in the classical NF-kappaB pathway. Chemical inhibition or knockdown of Flt3 with small interfering RNAs abolished NF-kappaB activation in MDS and AML cell lines, as well as in primary CD34+ bone marrow cells from patients, causing mitochondrial apoptosis. Epistatic analysis involving the simultaneous inhibition of Flt3 and IKK indicated that both kinases act via the same anti-apoptotic pathway. An IKK2 mutant with a constitutive kinase activity and a plasma membrane-tethered mutant of NEMO that activates IKK1/2 prevented the cytocidal action of Flt3 inhibition. IKK2 and Flt3 physically associated in MDS and AML cells and Flt3 inhibition caused the release of IKK2 from a preferential association with the plasma membrane. Flt3 inhibition only killed CD34+ bone marrow cells from high-risk MDS and AML patients, in correlation with the blast numbers and the NF-kappaB activity, yet had no lethal effect on healthy CD34+ cells or cells from low-risk MDS. These results suggest that Flt3 inhibitors might exert an anti-neoplastic effect in high-risk MDS and AML through inhibition of constitutive NF kappaB activation.

Poor Prognosis With Different Induction Rate Was Observed In Children With Acute Myeloid Leukemia and FLT3-ITD According To The ITD/WT Allelic Ratio: A Result From The Japanese Pediatric Leukemia/Lymphoma Study Group

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3891-3891
Author(s):  
Akira Shimada ◽  
Yuka Yamashita ◽  
Daisuke Tomizawa ◽  
Akio Tawa ◽  
Tomoyuki Watanabe ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Poor Prognosis ◽  
Pediatric Leukemia ◽  
Hematopoietic Stem ◽  
Allelic Ratio ◽  
Induction Rate ◽  
Wbc Count ◽  
Acute Myeloid

Abstract Background Acute myeloid leukemia harboring internal tandem duplication of fms-like tyrosine kinase 3 (AMLFLT3-ITD) is associated with poor prognosis, but the previous studies have reported that the inferior outcome is only confined to those with high allelic ratio (AR) of ITD/wild type (WT). In our previous AML99 study (2000-2002), AMLFLT3-ITD showed a poor outcome compared to the WT cases (5-year OS; 35% vs. 84%, P<0.0001). We, therefore, assigned all the patients with AMLFLT3-ITD to receive hematopoietic stem cell transplantation (HSCT) in first remission (1CR) in the JPLSG AML-05 study. Patients & Methods AML-05 study, registered at http://www.umin.ac.jp/ctr/ as UMIN000000511, is a Japanese nation-wide multi-institutional study for children (age<18 years) with de novo AML and enrolled 443 eligible patients from Nov. 2006 to Dec. 2010. Cases with acute promyelocytic leukemia or Down syndrome were excluded. FLT3-ITD was examined centrally for all the patients. After the 2 consecutive induction chemotherapies [(ECM: etoposide, Ara-C, and mitoxantrone) and (HCEI: HD Ara-C, etoposide, and idarubicin)], all the AMLFLT3-ITD patients were allocated to the high risk group and further received intensification therapy including HD Ara-C followed by HSCT in 1CR. All DNA samples were extracted from the first diagnostic bone marrow or peripheral blood and subjected to PCR and direct sequencing. AR of FLT3-ITD/WT was examined by GeneScan, and defined AR >0.4 as high and AR ≤ 0.4 as low as previously reported (Meshinchi S. Blood2006). Results We found 47 patients (10.6%) with AMLFLT3-ITD in this study (30 males, 17 females, and median age of 11 years at diagnosis). The median WBC count was 65,300/ml (3,690 - 522,050/mL). FAB classification included M1 (n=10), M2 (n=9), M4 (n=9), and M5 (n=11), and AML with normal karyotype was dominant (19/47, 40.4%). Of the 29 patients (61.7%) who achieved CR, twenty-seven received HSCT in 1CR and 19 patients survived (19/27, 70.4%). On the other hand, 14/16 non-CR patients received HSCT, but only 4 survived. The only demographic difference between the 29 CR and 16 non-CR cases was the median WBC count at diagnosis (19,000 vs. 124,000/μL, P<0.001), and rapid clearance of bone marrow blasts after single induction course was observed in the CR group (median blast percentage dropped from 73% to 1.1% in the CR group, while that was 85% to 30.6% in the non-CR group). Finally, five-year OS, DFS and EFS for all 47 AMLFLT3-ITD patients were 41.3%, 58.4% and 36.1%, respectively. AR was analyzed in 44 patients with median ratio of 0.68 (range, 0.11 to 4.47). Median AR was not different between CR vs. non-CR cases (0.53 vs. 0.72). There were no difference in 5-year OS (52.8% vs. 42.5%, P=0.302), DFS (54.5% vs. 64.5%, P=0.524), and EFS (50.0% vs. 34.4%, P=0.283) between patients with low (n=12) and high AR (n=32), however, induction rate was significantly higher in the low AR patients (91.7% vs. 53.1%, P=0.018). It was rather surprising that all FLT3-ITDs were found only in JM domain and not in TKI domain in the current trial. In addition, six of 47 (12.8%) AMLFLT3-ITD patients had NPM1mutation simultaneously, and all received HSCT at 1CR and survived. Discussion and Conclusion We observed a different induction rate between AMLFLT3-ITD patients with low and high AR, but poor final outcomes in both. Regardless of the level of AR, patients with AMLFLT3-ITD, especially who fail to achieve remission, have dismal outcome and effective therapy combined with novel FLT3 inhibitor is urgently needed to overcome the disease. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Acute Myeloid Leukemia with Basophilic Differentiation Transformed from Myelodysplastic Syndrome

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Yasuhiro Tanaka ◽  
Atsushi Tanaka ◽  
Akiko Hashimoto ◽  
Kumiko Hayashi ◽  
Isaku Shinzato
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Bone Marrow Failure ◽  
Immunosuppressive Treatment ◽  
Flow Cytometric Analysis ◽  
Chromosomal Analysis ◽  
Monosomy 7 ◽  
Acute Myeloid

Myelodysplastic syndrome (MDS) terminally transforms to acute myeloid leukemia (AML) or bone marrow failure syndrome, but acute myeloid leukemia with basophilic differentiation has been rarely reported. An 81-year-old man was referred to our department for further examination of intermittent fever and normocytic anemia during immunosuppressive treatment. Chromosomal analysis showed additional abnormalities involving chromosome 7. He was diagnosed as having MDS. At the time of diagnosis, basophils had not proliferated in the bone marrow. However, his anemia and thrombocytopenia rapidly worsened with the appearance of peripheral basophilia three months later. He was diagnosed as having AML with basophilic differentiation transformed from MDS. At that time, monosomy 7 was detected by chromosomal analysis. We found that basophils can be confirmed on the basis of the positivity for CD203c and CD294 by flow cytometric analysis. We also found by cytogenetic analysis that basophils were derived from myeloblasts. He refused any chemotherapy and became transfusion-dependent. He died nine months after the transformation. We should keep in mind that MDS could transform to AML with basophilic differentiation when peripheral basophilia in addition to myeloblasts develops in patients with MDS.

scholarly journals Development of Somatic NRAS Mutation Associated with Rapid Transition from Germline GATA2 Mutation Associated Myelodysplastic Syndrome to Acute Myeloid Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3616-3616 ◽  
Author(s):  
Yanqin Yang ◽  
Yubo Zhang ◽  
Jun Zhu ◽  
Catherine E. Lai ◽  
Jingrong Tang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Acute Myeloid Leukemia ◽  
Myelodysplastic Syndrome ◽  
Myeloid Leukemia ◽  
Research Funding ◽  
Bone Marrow Aspirate ◽  
Nras Mutation ◽  
Trisomy 8 ◽  
Acute Myeloid

Abstract There is increasing recognition of the role of inherited germline predisposition for myeloid disorders such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The additional somatic genetic events required for development of a malignant phenotype are however poorly understood. A 25 year old woman was referred to the NHLBI hematology branch in March 2014 for a seven year history of pancytopenia. Her medical history included recurrent pneumonias, oral ulcers, severe varicella infection and arthralgias. Prior bone marrow examinations at ages 21 and 23 at outside institutions reported normocellular marrow, tri-lineage hematopoiesis and mild dyspoiesis. Cytogenetics were remarkable for trisomy 8 in 80% (aged 21) or 90% (aged 23) of metaphases. Previously unrecognized lymphedema was noted on examination. Peripheral blood counts showed WBC 2.28 K/ul [normal range: 3.98-10.04], HGB 9.9 g/dL [11.2-15.7], PLT: 67 K/ul [173-369], ALC: 0.36 K/ul [1.18-3.74] and AMC: 0.06 [0.24-0.86]. Peripheral blood flow cytometry demonstrated decreased CD3+ CD4+ (T) cells, CD19+ (B) cells and NK cells. HLA-DR15 negative. Bone marrow examination showed trilineage hematopoiesis, 50-60% cellularity, mild erythroid predominance and mildly increased, mildly atypical megakaryocytes. Blasts less than 5%. Bone marrow flow cytometry revealed severely decreased B-cells and monocytes, absent B-cell precursors, absent dendritic cells, inverted CD4:CD8 ratio, and atypical myeloid maturation pattern. Cytogenetics demonstrated stable trisomy 8 in 90% of metaphases. On the basis of this assessment the diagnosis of MDS was confirmed. Sanger sequencing revealed a GATA2 L375S mutation in the second zinc finger of known pathogenic significance. Four months later she developed increased fatigue and easy bruising with worsening thrombocytopenia (PLT: 10K/ul). Bone marrow was dramatically changed; now markedly hypercellular (90-100%) with diffuse sheets of immature cells consistent with blasts having fine chromatin, distinct or prominent nucleoli, and visible cytoplasm. Blasts were positive for CD33, CD56, CD64, CD123, and CD163; and were negative for CD34, CD14, and myeloperoxidase. Cytogenetics showed a new trisomy 20 in 65% of metaphases, in addition to previously seen trisomy 8 in 100%. A diagnosis of acute monoblastic leukemia (M5a subtype) was made. At both clinic visits bone marrow aspirate was collected on an IRB approved research sample acquisition protocol. Whole exome sequencing of 1ug DNA was performed using Agilent SureSelect v5 Exome enrichment Kits on an Illumina HiSeq 2000 with 100-bp paired-end reads (Macrogen, Rockville, MD). Data was mapped to hg19 (BWA) and processed using an in-house pipeline (Samtools/Picard/GATK/VarScan/Annovar). Mean read depth of target regions was 157 and 149. There was high correlation between both samples with the exception of a NRAS:NM_002524:exon3:c.C181A:p.Q61K mutation (57 of 180 reads) seen only in the later sample. Confirmatory ultra-deep sequencing for NRAS was performed using Illumina TruSight Myeloid Sequencing Panel on an Illumina MiSeq. No evidence of the NRAS Q61K mutation was found in the earlier March MDS bone marrow sample even when sequenced to a depth greater than 1750 reads (see figure). The mutation was confirmed in the August AML sample at a variant allele frequency of 35%. If heterozygous this would reflect a clone size of 70%, consistent with data from both cytogenetics (new trisomy 20 in 65% of metaphases) and the 76% blasts documented by bone marrow aspirate smear differential. We report here the rapid progression to AML in a patient with germline GATA2 MDS associated with development of a new trisomy 20 karyotype and a NRAS Q61K mutation. The NRAS mutation was not detectable after the patient achieved a complete remission following induction chemotherapy further supporting this association. This NRAS mutation has been implicated in the pathogenesis of multiple cancers by constitutive activation of proliferative signaling. GATA2 associated MDS is a high-risk pre-leukemic condition with the potential for rapid evolution to AML. This is the first report of acquired somatic mutations in the RAS/RTK signaling pathway in the context of germline GATA2 insufficiency associated with acute leukemic transformation. Figure 1. Figure 1. Disclosures Townsley: Novartis: Research Funding; GSK: Research Funding.

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