scholarly journals Clinical Categorization of Chronic Myelomonocytic Leukemia into Proliferative and Dysplastic Subtypes Correlates with Distinct Genomic, Transcriptomic and Epigenomic Signatures

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1710-1710
Author(s):  
Ryan M. Carr ◽  
Terra Lasho ◽  
David Marks ◽  
Ezequiel Tolosa ◽  
Luciana L Almada ◽  
...  

Introduction: Chronic myelomonocytic leukemia (CMML), an aggressive myeloid malignancy, can be categorized into two subtypes, proliferative CMML (pCMML) and dysplastic (dCMML), based on a white blood cell (WBC) count of ≥ 13 x 109/L for the former (Arber et al. Blood 2016). While this WBC cut off is somewhat arbitrary, patients with pCMML have unique phenotypic features and a shorter survival. We carried out this study to assess the genomic, transcriptomic and epigenetic landscapes of these two CMML subtypes. Methods: Peripheral blood (PB) and bone marrow (BM) mononuclear cells (MNC) were obtained from WHO-defined CMML patients. Next generation sequencing (NGS) using a 36-gene panel was performed on 350 patients with Illumina HiSeq4000 platform with median read depth of 400X. RNA sequencing (RNA-seq) was performed on 25 patients by bulk whole transcriptome sequencing using Illumina TruSeq. DNA immunoprecipitation sequencing (DIP-seq) was performed on 18 patients using 5-methylcystocine (5mC), 5-hydroxymethylcytosine (5hmC) and bridging monoclonal antibodies with subsequent paired-end sequencing using HiSeq4000. Chromatin immunoprecipitation sequencing (ChIP-seq) was performed on 30 patients with Illumina HiSeq2500 to a depth of 25 million for histone 3 lysine 4 monomethylation (H3K4me1) and histone 3 lysine 4 trimethylation (H3K4me3) and 50 million reads for histone 3 lysine 27 trimethylation (H3K27me3) and Input per sample. Results: Five hundred and seventy-three patients with WHO defined CMML were included; median age 71 years (range 18-95 years), 67% males. 282 patients had pCMML (49%), while 291 (51%) had dCMML. As pre-defined, patients with pCMML were more likely to have higher absolute monocyte counts (p<0.0001), circulating immature myeloid cells (p<0.0001), PB blasts (p<0.0001), and higher lactate dehydrogenase levels (p=0.03). At last follow up 234 (41%) deaths and 70 (20%) leukemic transformations were documented. The median OS for pCMML vs dCMML in this cohort was 19 months vs 30 months (p<0.0001, Figure 1A) and validated in an independent Austrian cohort (p=0.02). Genomic profiling: NGS performed on 350 patients (BM MNC) revealed a higher frequency of NRAS (35 vs 17%, p=0.004), cumulative RAS pathway (NRAS, KRAS, CBL and PTPN11) (73 vs 47%, p=0.001), ASXL1 (p=0.003) and JAK2V617F (p=0.04) mutations in pCMML relative to dCMML (Figure 1B); while dCMML had a higher frequency of SF3B1 mutations (p=0.02). There were no differences in distribution of TET2 and SRSF2Transcriptomic analysis: RNA-seq was performed on PB MNC from RAS pathway mutant pCMML patients (n=12) and RAS pathway wildtype dCMML patients (n=13). Unsupervised clustering analysis resulted in appropriate segregation revealing distinct expression profiles between disease subtypes (Figure 1C). Compared to dCMML, 3729 genes were significantly differentially upregulated and 2658 genes were differentially downregulated in pCMML. Among genes most highly upregulated were mitotic checkpoint kinases including AURBK, PLK1, PLK2, PLK4 andEpigenetic profiling: ChIP-seq of PB and BM MNC from pCMML (n=18) and dCMML (n=12) patients and healthy, age-matched controls (n=10) revealed a global increase in H3K4me1, without significant differences in H3K4me3 or H3K27me3 occupancies (regardless of stratification by ASXL1 mutational status; 40% ASXL1mt in pCMML, 30% dCMML) in pCMML vs dCMML (Figure 1D). H3K4me1 occupancy was also increased in a sequence-specific manner at the transcription start sites of the aforementioned mitotic kinases (PLK1 and WEE1). DIP-seq was performed on PB MNC to assess global differences in 5-mC and 5-hmC levels, between pCMML (n=9) and dCMML (n=9), with no differences seen between the two subtypes (regardless of TET2 mutational status, 40% TET2mt in each subtype) (Figure 1E). Conclusions: Despite the somewhat arbitrary WBC distinction between pCMML and dCMML, clear phenotypic, genetic, transcriptomic, epigenetic and survival differences exist between the two subtypes, providing strong biological rationale for this distinction. pCMML patients have a higher frequency of oncogenic RAS pathway mutations, a unique transcriptomic profile enriched in mitotic check point kinases and a unique chromatin configuration with global and sequence specific enrichment in H3K4me1, with no significant global differences in 5mC, 5hmC, or H3K4me3 and H3K27me3 occupancy. Figure 1 Disclosures Geissler: AOP: Honoraria; Pfizer: Honoraria; AstraZeneca: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Roche: Honoraria; Abbvie: Honoraria; Ratiopharm: Honoraria; Amgen: Honoraria. Al-Kali:Astex Pharmaceuticals, Inc.: Research Funding. Patnaik:Stem Line Pharmaceuticals.: Membership on an entity's Board of Directors or advisory committees.

2020 ◽  
Vol 21 (8) ◽  
pp. 3025 ◽  
Author(s):  
Klaus Geissler ◽  
Eva Jäger ◽  
Agnes Barna ◽  
Michael Gurbisz ◽  
Temeida Graf ◽  
...  

Although the RAS-pathway has been implicated as an important driver in the pathogenesis of chronic myelomonocytic leukemia (CMML) a comprehensive study including molecular and functional analyses in patients with progression and transformation has not been performed. A close correlation between RASopathy gene mutations and spontaneous in vitro myeloid colony (CFU-GM) growth in CMML has been described. Molecular and/or functional analyses were performed in three cohorts of 337 CMML patients: in patients without (A, n = 236) and with (B, n = 61) progression/transformation during follow-up, and in patients already transformed at the time of sampling (C, n = 40 + 26 who were before in B). The frequencies of RAS-pathway mutations (variant allele frequency ≥ 20%) in cohorts A, B, and C were 30%, 47%, and 71% (p < 0.0001), and of high colony growth (≥20/105 peripheral blood mononuclear cells) 31%, 44%, and 80% (p < 0.0001), respectively. Increases in allele burden of RAS-pathway mutations and in numbers of spontaneously formed CFU-GM before and after transformation could be shown in individual patients. Finally, the presence of mutations in RASopathy genes as well as the presence of high colony growth prior to transformation was significantly associated with an increased risk of acute myeloid leukemia (AML) development. Together, RAS-pathway mutations in CMML correlate with an augmented autonomous expansion of neoplastic precursor cells and indicate an increased risk of AML development which may be relevant for targeted treatment strategies.


Author(s):  
Ryan M. Carr ◽  
Denis Vorobyev ◽  
Terra Lasho ◽  
David L. Marks ◽  
Ezequiel J. Tolosa ◽  
...  

ABSTRACTChronic myelomonocytic leukemia (CMML) is an aggressive hematological malignancy with limited treatment options. Whole exome (WES) and targeted sequencing of several independent cohorts of CMML patients, comparing dysplastic (dCMML) to proliferative (pCMML) CMML, as well as paired chronic phase disease and acute leukemic transformation (LT), associate acquisition of oncogenic RAS pathway mutations, the most common being NRASG12D, with aggressive disease and with disease progression. Using patient derived progenitor colony assays and a NRASG12D-Vav-Cre mouse model, we further demonstrate the role of mutant RAS signaling in driving and maintaining pCMML phenotype. RNA-sequencing links RAS pathway mutations with an increased expression of genes encoding the mitotic checkpoint kinases PLK1 and WEE1. Further, we dmeoinstrated that non-mutated lysine methyltransferase KMT2A (MLL1) acts as mediator of NRAS-induced PLK1 and WEE1 expression. Finally, we demonstrate the translational value of our findings by showing that pharmacological PLK1 inhibition decreases monocytosis and hepatosplenomegaly while improving hematopoiesis in RAS mutant patient-derived xenografts. Hence, we define severe CMML as oncogenic RAS pathway-enriched malignancies, with a unique gene expression profile regulated by KMT2A, amenable to therapeutic intervention.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryan M. Carr ◽  
Denis Vorobyev ◽  
Terra Lasho ◽  
David L. Marks ◽  
Ezequiel J. Tolosa ◽  
...  

AbstractProliferative chronic myelomonocytic leukemia (pCMML), an aggressive CMML subtype, is associated with dismal outcomes. RAS pathway mutations, mainly NRASG12D, define the pCMML phenotype as demonstrated by our exome sequencing, progenitor colony assays and a Vav-Cre-NrasG12D mouse model. Further, these mutations promote CMML transformation to acute myeloid leukemia. Using a multiomics platform and biochemical and molecular studies we show that in pCMML RAS pathway mutations are associated with a unique gene expression profile enriched in mitotic kinases such as polo-like kinase 1 (PLK1). PLK1 transcript levels are shown to be regulated by an unmutated lysine methyl-transferase (KMT2A) resulting in increased promoter monomethylation of lysine 4 of histone 3. Pharmacologic inhibition of PLK1 in RAS mutant patient-derived xenografts, demonstrates the utility of personalized biomarker-driven therapeutics in pCMML.


2021 ◽  
Author(s):  
Wu Biao ◽  
Yufeng Chen ◽  
Junlong Zhong ◽  
Shuping Zhong ◽  
Bin Wang ◽  
...  

Abstract Background: Rheumatoid arthritis (RA) is a common autoimmune disease that can occur at any age. If treatment is delayed, RA can seriously affect the patients’ quality of life. However, there is no diagnostic criteria for RA and the positive predictive value of the current biomarkers is moderate. Objective: to identify RA-associated susceptibility genes and explore their potential as a novel biomarker for diagnosis and evaluation of the prognosis of RA.Methods: Peripheral blood mononuclear cells (PBMCs) were collected from healthy human donors and RA patients. RNA-seq analyses were performed to identify the differentially expressed genes (DEGs) between RA and control samples. The PBMCs-mRNA in DEGs were further subjected to enrichment analysis. Furthermore, the hub genes and key modules associated with RA were screened by bioinformatics analyses. Then, the expression of hub genes in RA were assessed in mRNA expression profiles. Next, real time-quantitative PCR (RT-qPCR) analyses were performed to further confirm the expression of the hub genes from the PBMCs that collected from 47 patients with RA and 40 healthy controls. Finally, we evaluated the clinical characters for the candidate mRNAs.Results: RNA-seq analyses revealed the expression of 178 mRNAs from PBMCs were disregulated between the healthy controls and the RA patients. Bioinformatics analyses revealed 10 hub mRNAs. The top 3 significant functional modules screened from PPI network functionally were involved in DNA replication origin binding, chemokine activity, etc. After validating the 10 hub mRNAs in GSE93272 dataset and clinical samples, we identified 3 candidate mRNAs, including ASPM, DTL and RRM2. Among which, RRM2 showed great capacity in discriminating between remissive RA and active RA. Significant correlations were observed between DTL and IL-8, TNF-α, between RRM2 and CDAI, DAS-28, tender joints and swollen joints, respectively. The AUC values of ASPM, DTL and RRM2 were 0.654, 0.995 and 0.990, respectively.Conclusion: We successfully identified multiple candidate mRNAs associated with RA. RRM2 showed high diagnosis efficiency with the AUC of 0.990 (sensitivity=100%, specificity=97.5%). And RRM2 severed as an additional biomarker for evaluating disease activity. The findings provided a novel candidate biomarker for diagnosis and evaluation of the prognosis of RA.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2699-2699
Author(s):  
Mehdi Nassiri ◽  
Joseph Olczyk ◽  
Samantha Knapp ◽  
Gail Vance ◽  
Anupama Tewari ◽  
...  

Abstract Chronic myelomonocytic leukemia (CMML) is a hematopoietic malignancy with hybrid myeloproliferative and myelodysplastic features. The diagnostic criteria for CMML are evolving with the progress of our knowledge on various genetic lesions involved in the pathogenesis of myeloid neoplasms. This shift, including molecular genetic lesions in the diagnosis process, is highlighted in updated 2008 WHO classification system, which excludes myeloproliferative neoplasms with PDGFRB rearrangement, monocytosis and eosinophilia from CMML category. Despite these recent advancements, CMML remains a heterogeneous group of diseases with variable patient outcomes and no well-defined targeted therapy. To further investigate the biological diversity of this disorder, we studied microRNA (miRNA) expression profiles, their relation to the diagnostic and clinical parameters in CMML, and compared these profiles to global miRNA expression in normal reference bone marrow samples. MicroRNAs are a class of non-coding RNA molecules that alter gene expression by targeting and blocking mRNA. The role of miRNAs in carcinogenesis is related to their targeting of messenger RNAs encoding for oncogenes and tumor suppressor genes. Bone marrow samples from 22 patients with CMML were included in the study. Median age of the patients was 71 years with a range from 39 to 92 years. There were 15 males and 7 females. Seventeen patients presented with CMML-1 (blasts less than 5% in peripheral blood and less than 10% of bone marrow differential count). The remaining patients showed CMML-2. Nine patients had WBC below 13×109/L defining a myelodysplastic type of CMML. Cytogenetic results were available in 20 patients. Fourteen patients demonstrated a normal karyotype. Normal pooled bone marrow samples were used as a reference. The total RNA was isolated using RecoverAll RNA extraction kit. Micoroarray studies were performed using Agilent human miRNA microarrays (version 1.0) containing probes for 470 human and 64 human viral miRNAs cataloged in the Sanger database v9.1. The results were analyzed using BRB array tool and Genesis software. Unsupervised hierarchical clustering discovered two different groups of CMML samples with patterns of miRNA expression distinct from normal bone marrows (oneway ANOVA). Twenty seven miRNAs were differentially expressed in normal bone marrow reference samples vs. CMML-1 and -2. There was an overlap in miRNA profiles between groups of CMML based on blast percentage (CMML-1 vs. CMML-2), WBC count (&lt;13×109/L vs. ≥13×109/L) and presence or absence of cytogenetic abnormalities. However, using PAM algorithm the following miRNAs showed predictive power: hsa-miR-519b (in CMML-1 vs. 2); hsa-miR-15b and hsa-miR-432* (in groups of samples separated by a cut-off WBC of 13×109/L) and hsa-miR-223 (comparing CMML with and without cytogenetic abnormalities). In summary, significantly different miRNA profiles were seen in CMML as compared to normal reference bone marrow. Two distinct subgroups of CMML were defined by the miRNA expression profiles. Select miRNAs were differentially expressed in known biological and clinical subgroups of CMML. Further correlation of clinical and outcome data with subgroups of CMML defined by miRNA expression profiles will be presented.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 296-296 ◽  
Author(s):  
Vera Grossmann ◽  
Alexander Kohlmann ◽  
Christiane Eder ◽  
Nicholas C.P. Cross ◽  
Claudia Haferlach ◽  
...  

Abstract Abstract 296 Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic malignancy that is characterized by features of both a myeloproliferative neoplasm and a myelodysplastic syndrome. Recently, we investigated 81 CMML cases (45 CMML-1, 36 CMML-2) diagnosed between 10/2005 - 9/2008, which had been characterized by chromosome banding analysis and mutation analysis in 6 candidate genes: Mutations were detected in TET2 (44.4%), CBL (22.2%), NRAS (22.2%), KRAS (12.3%), JAK2 (9.8%), RUNX1 (8.7%) (Kohlmann et al., J Clin Oncol. 2010 Jul 19). We now applied amplicon-based deep-sequencing using the small volume Titanium chemistry assay (454 Life Sciences, Branford, CT) to investigate additional 4 candidate genes: IDH1 (exon 4), IDH2 (exon 4) and NPM1 (exon 12) (at known mutational hotspot regions) and the complete coding region of EZH2. EZH2 encodes a catalytic subunit of the polycomb repressive complex 2, a highly conserved histone H3 lysine 27 methyltransferase that influences stem cell renewal. Mutations in EZH2 were recently described to play a role in MPN/MDS. The sequencing library preparation for IDH1, IDH2, NPM1, and EZH2, in total 22 amplicons, was performed using 48.48 Access Array technology (Fluidigm, South San Francisco, CA) to cope with the number of amplicons. In median, 498 reads per amplicon were obtained, thus yielding sufficient coverage for detection of mutations with high sensitivity. After excluding polymorphisms and silent mutations aberrations were detected in IDH1 (1/81; 1.2%), IDH2 (3/81; 3.7%), NPM1 (1/81; 1.2%), and EZH2 (10/81; 12.3%). Another gene recently described in hematological diseases is ASXL1 (additional sex combs like 1) on chromosome 20q11.1. Therefore, the hotspot region of ASXL1 exon 12 was additionally investigated by Sanger sequencing in those 20 cases, in which no mutation had been observed thus far. Nine of these 20 cases (45%) harbored a mutation in ASXL1, thus only 11 cases (13.6%) remained in this cohort in which no mutation was detected. Summarizing this data, 86.4% of these CMMLs harbored at least one molecular aberration with a median of two genes mutated (range 1–4). In more detail, we observed 11 novel distinct EZH2 mutations in ten patients: 7 missense, 3 frameshifts (2 deletions, 1 insertion), and one splice site mutation. EZH2 mutations were found to be heterogeneous and were spread over several exons, predominantly located in the four conserved regions (6/11 in the conserved SET domain; e.g. H680R, N659S). No case revealed a Tyr641 of EZH2 mutation as described for follicular and diffuse large B-cell lymphomas. In median, the burden of EZH2 mutations was 42.5% of sequencing reads per patient (range 1.4–98%). Similarly, a high mutation burden was detected in RUNX1 (median 46.7%), TET2 (median 44.6%), and CBL (median 42.5%) whereas the burden was low in RAS pathway alterations, i.e. NRAS (median 11.1%), KRAS (median 27%), or JAK2 V617F mutations (median 6.9%). With respect to associations of distinct mutations no specific pattern was observed, i.e. EZH2 mutations were concomitantly detected with TET2 (4/10), RUNX1 (3/10), CBL (3/10), JAK2 (3/10), NRAS (2/10), KRAS (1/10), and IDH2 (1/10), respectively. Further, EZH2 mutations were associated neither with morphologic CMML subtype or dysplastic or myeloproliferative characteristics nor with age, white blood cell count, thrombocytes count, or hemoglobin. However, with respect to clinical data a very poor outcome was observed for patients that carried EZH2 mutations compared to EZH2 wild-type cases (median OS 4.3 vs. 130.4 months; p<0.001). In contrast, a significantly better outcome was seen for patients who carried TET2 mutations compared to TET2 wild-type cases (median OS 130.4 vs. 53.6 months, p=0.013). Subsequently, we performed a survival analysis taking both EZH2 and TET2 mutations into account. Here, the cohort was significantly separated into three distinct prognostic groups, i.e. EZH2-mutated with a poor median OS of 4.3 months, EZH2/TET2 wild-type with a median OS of 90 months and TET2-mutated cases with a median OS of 130.4 months (p<0.001). In conclusion, our study revealed molecular mutations in 86.4% of 81 CMML patients providing new insights into the molecular heterogeneity of this disease. Besides alterations in TET2, CBL, ASXL1, and the RAS pathway, EZH2 is targeted by various types of frameshift and point mutations and is a novel biomarker with unfavorable prognosis and clinical utility. Disclosures: Grossmann: MLL Munich Leukemia Laboratory: Employment. Kohlmann:MLL Munich Leukemia Laboratory: Employment. Eder:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership, Research Funding. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.


2021 ◽  
Author(s):  
Yingying Zhou ◽  
Yuqing Huang ◽  
Tielong Chen ◽  
Wenjia Hu ◽  
Xiaoping Chen ◽  
...  

Abstract Background: Many studies have shown that long noncoding RNAs (lncRNAs) derived from the host and human immunodeficiency virus (HIV) itself play important roles in virus-host interactions and viral pathogenesis. To identify potential key lncRNAs in the regulation of HIV pathogenesis, transcriptome analysis of peripheral blood mononuclear cells (PBMCs), which were derived from 6 HIV/acquired immunodeficiency syndrome (AIDS) subjects pre-HAART and post-HAART with effective control of plasma viremia (<20 HIV RNA copies/ml) and 6 healthy subjects, was performed by RNA sequencing (RNA-seq).Results: We identified a total of 974 lncRNAs whose expression levels were restored to normal after ART therapy. The results of the cis-acting analysis showed that only six lncRNAs have cis-regulated target genes, among which the target gene RP11-290F5.1, interferon regulatory factors 2 (IRF2), could promote HIV replication. We also identified lncRNA CTB-119C2.1, which regulates most mRNAs with differential expression between pre- and post-HAART, and the differences were significant. We selected lncRNA CTB-119C2.1 for qRT–PCR verification, and the results were consistent with those of RNA-seq. RAB3A and GADD45A, two of the lncRNA CTB-119C2.1-associated genes, have been shown to be associated with HIV infection. KEGG analysis of lncRNA CTB-119C2.1-associated genes revealed that most of the genes are involved in the p53 signaling pathway or pathways related to cell circulation and DNA replicationConclusion: In this study, we used RNA-seq to systematically compare the expression profiles of lncRNAs in HIV subjects between untreated and treated time points. We successfully identified some lncRNAs with differential expression during certain periods (no HIV infection, HIV infection before treatment, and after treatment). Their expression is associated with viral loads, and some of their regulating genes were found to be involved in HIV pathogenesis through bioinformatic analysis. These findings could help to reveal the underlying molecular mechanism of the progression of AIDS.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4602-4602
Author(s):  
Andrica C.H. de Vries ◽  
Ronald W. Stam ◽  
Christian Kratz ◽  
Martin Zenker ◽  
Oskar A. Haas ◽  
...  

Abstract Approximately 75% of patients with juvenile myelomonocytic leukemia (JMML) harbour mutations in PTPN11, NF1 and RAS genes. The remaining cases presumably carry somatic mutations in other genes in the RAS pathway. BRAF plays a central role in this pathway between RAS and downstream molecules including MEK and ERK. BRAF mutations frequently occur in cancer. Recently, BRAF mutations were found in leukemia. Besides that, germline BRAF mutations cause cardio-facio-cutaneous syndrome, which shares many features with Noonan syndrome (NS). NS predisposes to a myeloproliferative disease resembling JMML. In 65 JMML patients screening for V600E mutations in exon 15 of the BRAF gene was performed from mononuclear cells. In a subset of patients, without RAS or PTPN11 mutations, and no clinical signs of NF1, the entire coding sequence of BRAF was analyzed. Sequence analysis was performed by direct, bidirectional sequencing of purified polymerase chain reaction products. In none of the 65 cases a V600E mutation of the BRAF gene was found. In a subset of patients in which the entire coding sequence of BRAF was analyzed, no mutations were identified either. Mutant proteins of the RAS-RAF-MEK-ERK pathway play an important role in the pathogenesis of JMML, resulting in GM-CSF hypersensitivity. In about 75% of the JMML cases these mutations affect RAS, NF1 or PTPN11 genes. The hypothesis for this study was that BRAF might play an important role in JMML as it is an important downstream effector of RAS. Our data show that apparently BRAF mutations do not play a role in JMML. Therefore, additional analysis of genes of the RAS pathway will be necessary to identify genetic aberrations in cases without known mutations.


Blood ◽  
2006 ◽  
Vol 108 (7) ◽  
pp. 2349-2357 ◽  
Author(s):  
Chaitali Parikh ◽  
Ramesh Subrahmanyam ◽  
Ruibao Ren

Abstract Activating mutations in RAS, predominantly NRAS, are common in myeloid malignancies. Previous studies in animal models have shown that oncogenic NRAS is unable to induce myeloid malignancies effectively, and it was suggested that oncogenic NRAS might only act as a secondary mutation in leukemogenesis. In this study, we examined the leukemogenicity of NRAS using an improved mouse bone marrow transduction and transplantation model. We found that oncogenic NRAS rapidly and efficiently induced chronic myelomonocytic leukemia (CMML)– or acute myeloid leukemia (AML)– like disease in mice, indicating that mutated NRAS can function as an initiating oncogene in the induction of myeloid malignancies. In addition to CMML and AML, we found that NRAS induced mastocytosis in mice. This result indicates that activation of the RAS pathway also plays an important role in the pathogenesis of mastocytosis. The mouse model for NRAS leukemogenesis established here provides a system for further studying the molecular mechanisms in the pathogenesis of myeloid malignancies and for testing relevant therapies.


2013 ◽  
Vol 31 (19) ◽  
pp. 2428-2436 ◽  
Author(s):  
Raphaël Itzykson ◽  
Olivier Kosmider ◽  
Aline Renneville ◽  
Véronique Gelsi-Boyer ◽  
Manja Meggendorfer ◽  
...  

Purpose Several prognostic scoring systems have been proposed for chronic myelomonocytic leukemia (CMML), a disease in which some gene mutations—including ASXL1—have been associated with poor prognosis in univariable analyses. We developed and validated a prognostic score for overall survival (OS) based on mutational status and standard clinical variables. Patients and Methods We genotyped ASXL1 and up to 18 other genes including epigenetic (TET2, EZH2, IDH1, IDH2, DNMT3A), splicing (SF3B1, SRSF2, ZRSF2, U2AF1), transcription (RUNX1, NPM1, TP53), and signaling (NRAS, KRAS, CBL, JAK2, FLT3) regulators in 312 patients with CMML. Genotypes and clinical variables were included in a multivariable Cox model of OS validated by bootstrapping. A scoring system was developed using regression coefficients from this model. Results ASXL1 mutations (P < .0001) and, to a lesser extent, SRSF2 (P = .03), CBL (P = .003), and IDH2 (P = .03) mutations predicted inferior OS in univariable analysis. The retained independent prognostic factors included ASXL1 mutations, age older than 65 years, WBC count greater than 15 ×109/L, platelet count less than 100 ×109/L, and anemia (hemoglobin < 10 g/dL in female patients, < 11g/dL in male patients). The resulting five-parameter prognostic score delineated three groups of patients with median OS not reached, 38.5 months, and 14.4 months, respectively (P < .0001), and was validated in an independent cohort of 165 patients (P < .0001). Conclusion A new prognostic score including ASXL1 status, age, hemoglobin, WBC, and platelet counts defines three groups of CMML patients with distinct outcomes. Based on concordance analysis, this score appears more discriminative than those based solely on clinical parameters.


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