MDS) And Myelodysplastic/myeloproliferative Neoplasms Research Articles

Deep immunophenotypic analysis of the bone marrow progenitor cells in myelodysplastic syndromes

BackgroundDiagnosis of myelodysplastic syndromes (MDS) is often challenging and requires integration of clinical, morphologic, cytogenetics and molecular information. Flow cytometry immunophenotyping (FCIP) can support the diagnosis by demonstration of numerical and immunophenotypic abnormalities of progenitor and maturing myelomonocytic and erythroid populations. We have previously shown that comprehensive immunophenotypic analysis of the progenitor population is valuable in the diagnosis of MDS and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). This study was designed to improve the analysis method and confirm its value in a larger cohort of patients. MethodsFCIP of bone marrow samples from 105 patients with cytopenia(s) (with or without leukocytosis) and clinical concern for MDS or MDS/MPN was performed using a single-tube/10-color/13-marker assay. A modified analysis approach was used to obtain 11 progenitor parameters and 2 myelomonocytic parameters. ResultsSignificantly higher number of abnormalities were identified in MDS and MDS/MPN cases when compared to cytopenic patients not meeting the diagnostic criteria for MDS (Non-MDS). A FCIP score that combined the 13 parameters showed a sensitivity of 89.8% and specificity of 93.5% for the diagnosis of MDS and MDS/MPN. The sensitivity was 100% for both MDS/MPN and higher-risk MDS, and 81.3% for lower-risk MDS. ConclusionThis study confirms that detailed immunophenotypic analysis of the progenitor population is powerful in the diagnosis of MDS and MDS/MPN. The combination of markers used in the panel allowed for evaluation of two relatively new parameters, namely myeloid progenitor heterogeneity and stem cell aberrancy, which improved the sensitivity of the assay for lower-risk MDS.

Auer rods and faggot cells: A review of the history, significance and mimics of two morphological curiosities of enduring relevance.

Myeloid differentiation in blasts is distinguished by the presence of one or more needle-shaped crystalline structures called Auer rods. Auer rods manifest either alone or as faggot cells (containing bundles of Auer rods) in various types of acute myeloid leukemia (AML), myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). Their presence largely portends a better prognosis in AML (as markers of maturation/differentiation) and upstages cases of MDS and MDS/MPN. Observation of these rods in residual blasts in treated cases of AML indicates an absence of remission. This article traces their historical discovery and examines their pathogenetic intricacies, as well as our current understanding of their relevance in myeloid neoplasms. Studies evaluating their prognostic impact in AML and MDS are catalogued. We also discuss a variety of other hematological and non-hematological neoplasms where structures potentially mistakable for Auer rods have been described. Even as the diagnostic approach to hematological malignancies has evolved from a morphology + cytochemistry + immunophenotyping-dependent one in the last century to a predominantly molecular genetics-based classification currently, and even as high-throughput sequencing and structural variation detection techniques surpass morphology in detecting clinically-relevant sub-categories of similar-appearing tumours, we review these curious microscopic structures that have withstood the test of time with respect to their diagnostic relevance.

A Pilot Clinical Study to Investigate the Hypomethylating Properties of Freeze-dried Black Raspberries in Patients with Myelodysplastic Syndrome or Myeloproliferative Neoplasm.

Myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are bone marrow disorders characterized by cytopenias and progression to acute myeloid leukemia. Hypomethylating agents (HMAs) are Food and Drug Administration-approved therapies for MDS and MDS/MPN patients. HMAs have improved patients’ survival and quality of life when compared with other therapies. Although HMAs are effective in MDS and MDS/MPN patients, they are associated with significant toxicities that place a large burden on patients. Our goal is to develop a safer and more effective HMA from natural products. We previously reported that black raspberries (BRBs) have hypomethylating effects in the colon, blood, spleen, and bone marrow of mice. In addition, BRBs exert hypomethylating effects in patients with colorectal cancer and familial adenomatous polyposis. In the current study, we conducted a pilot clinical trial to evaluate the hypomethylating effects of BRBs in patients with low-risk MDS or MDS/MPN. Peripheral blood mononuclear cells (PBMCs) were isolated before and after three months of BRB intervention. CD45+ cells were isolated from PBMCs for methylation analysis using a reduced-representation bisulfite sequencing assay. Each patient served as their own matched control, with their measurements assessed before intervention providing a baseline for post-intervention results. Clinically, our data showed that BRBs were well-tolerated with no side effects. When methylation data was combined, BRBs significantly affected methylation levels of 477 promoter regions. Pathway analysis suggests that BRB-induced intragenic hypomethylation drives leukocyte differentiation. A randomized, placebo-controlled clinical trial of BRB use in low-risk MDS or MDS/MPN patients is warranted.

The utility of a myeloid mutation panel for the diagnosis of myelodysplastic syndrome and myelodysplastic/myeloproliferative neoplasm.

The diagnosis of myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) is based on morphology and cytogenetics/FISH findings per 2017 WHO classification. With rare exceptions, somatic mutations have not been incorporated as the diagnostic criteria. We analyzed the utility of mutational analysis with a targeted 54-gene or 40-gene next-generation sequencing (NGS) panel in the diagnosis of MDS and MDS/MPN. We retrospectively collected92 patientswho presented withunexplained cytopenia with or withoutcytosis, including 32 low-grade MDS (MDS-L), 18 high-grade MDS (MDS-H), 5 therapy-related MDS (MDS-TR), 19 MDS/MPN, and 18 negative cases. Of 92 patients, 197 somatic mutations involving 38 genes were detectedand hadvariant allele frequency (VAF) ranging from 3%to99%.The most common mutated genes wereTET2, ASXL1, RUNX1, TP53, SRSF2, and SF3B1. MDS-L, MDS-H, MDS-TR, and MDS/MPN showed an average number of somatic mutations with a mean VAF of 1.9/33%, 2.6/30%, 2/36%, and 4/41%,respectively. SF3B1 mutations were exclusively observed in MDS-L and MDS/MPN. TP53 gene mutations were more frequently seen in MDS-H and MDS-TR. Among 34 patients with a diagnosis of MDS or MDS/MPN with normal cytogenetics, 31 patients (91%) had at least 1 mutation and 24 patients (71%) had ≥2 mutations with ≥10% VAF. A myeloid mutational panel provides additional evidence of clonality besides cytogenetics/FISH studies in the diagnosis of cytopenia with or without cytosis. Two or more mutations with ≥10% VAF highly predicts MDS and MDS/MPN with a positive predictive value of 100%.

Exploring blast composition in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms: CD45RA and CD371 improve diagnostic value of flow cytometry through assessment of myeloblast heterogeneity and stem cell aberrancy.

BackgroundFlow cytometry immunophenotyping (FCIP) can improve diagnosis of myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN), although its application is challenging due to difficulties in standardization, complexity of antibody panels and subjective interpretation of data. Since blasts are invariably affected in these disorders, we developed a FCIP approach for detailed and objective analysis of the blast population.MethodsFCIP using a one‐tube 10‐color (13‐marker) antibody panel was performed on bone marrow samples from 23 MDS and 8 MDS/MPN patients, 21 cytopenic patients non‐diagnostic for MDS (Non‐MDS), and 16 Control samples.ResultsMDS and MDS/MPN cases demonstrated one to several immunophenotypic abnormalities including: increased myeloblasts, decreased stage‐1 hematogones, aberrant stem cells, abnormal myeloblast heterogeneity/divergence from normal, increased or decreased CD45 intensity, increased CD117 or CD123 intensity, decreased CD38 intensity, and aberrant expression of lineage markers (CD5, CD19, CD56). A Blast score was developed that showed sensitivity of 80.6% and specificity of 90.5% for immunophenotypic diagnosis of MDS and MDS/MPN. Expression levels of CD45RA and CD371 were used to evaluate abnormal myeloblast heterogeneity and stem cell aberrancy. Both these features were, for the first time, incorporated into a scoring system and resulted in 19% increase in the sensitivity of the assay for lower‐risk MDS.ConclusionDeep immunophenotypic analysis of the blast population is valuable for diagnosis of MDS and MDS/MPN and can potentially provide sensitivity and specificity figures comparable to those previously described using more comprehensive panels that assess maturing myelomonocytic and erythroid elements in addition to progenitor cells.

Clinical Applications of Chromosomal Microarray Testing in Myeloid Malignancies

Knowledge of both somatic mutations and copy number aberrations are important for the understanding of cancer pathogenesis and management of myeloid neoplasms. The currently available standard of care technologies for copy number assessment such as conventional karyotype and FISH are either limited by low resolution or restriction to targeted assessment. Chromosomal microarray (CMA) is effective in characterization of chromosomal and gene aberrations of diagnostic, prognostic, and therapeutic significance at a higher resolution than conventional karyotyping. These results are complementary to NGS mutation studies. Copy-neutral loss of heterozygosity (CN-LOH), which is prognostic in AML, is currently only identified by CMA. Yet, despite the widespread availability, CMA testing is not routinely performed in diagnostic laboratories due to lack of knowledge on best-testing practices for clinical work-up of myeloid neoplasms. In this review, we provide an overview of the clinical significance of CMA in acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). We will also elaborate the specific clinical scenarios where CMA can provide additional information essential for management and could potentially alter treatment. Chromosomal microarray (CMA) is an effective technology for characterizing chromosomal copy number changes and copy-neutral loss of heterozygosity of diagnostic, prognostic, and therapeutic significance at a high resolution in myeloid malignancies.

Conditioning Regimen of 5-Day Decitabine Administration for Allogeneic Stem Cell Transplantation in Patients with Myelodysplastic Syndrome and Myeloproliferative Neoplasms.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for patients with myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). However, post-HSCT relapse remains a major cause of treatment failure. Here we assessed the efficacy of a new conditioning regimen comprising decitabine (Dec), busulfan (Bu), cyclophosphamide (Cy), fludarabine (Flu), and cytarabine (Ara-c) for allo-HSCT in patients with MDS and MDS/MPN. A total of 48 patients were enrolled, including 44 with MDS and 4 with chronic myelomonocytic leukemia (CMML). Patients received Dec 20 mg/m2/day on days -9 to -5, combined with a Bu/Cy/Flu/Ara-c-modified preparative regimen. At a median follow-up of 522 days (range, 15 to 1313 days), the overall survival (OS) was 86%, relapse incidence was 12%, and nonrelapse mortality was 12%. The incidence of severe acute (grade III-IV) graft-versus-host disease (GVHD) was 23% and that of chronic GVHD was 15%. At 2 years, OS was 74% and 86%, respectively for high-risk and very-high-risk patients with MDS. Survival was promising in patients with poor-risk gene mutations, such as TP53 and ASXL1 (88%), and in those with ≥3 gene mutations (79%). Results of immunomonitoring studies revealed that proper natural killer cells made essential contributions to these favorable clinical outcomes. Overall, this new regimen was associated with a low relapse rate, low incidence and severity of GVHD, and satisfactory survival in allo-HSCT recipients with MDS and MDS/MPN.

Genomic aberrations in myelodysplastic syndromes and related disorders

Myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are heterogeneous myeloid neoplasms that frequently evolve into secondary acute myeloid leukemia (sAML). Recent progress in next-generation sequencing technologies has allowed us to discover frequent mutations throughout the coding regions of MDS, MDS/MPN, and sAML, subsequently providing information on more than 60 driver genes in these diseases. As shown by many study groups recently, such driver mutations are acquired in a gene-specific fashion. DDX41 and SAMD9/SAMD9L mutations are observed in germline cells long before MDS presentation. In blood samples from healthy elderly individuals, somatic DNMT3A, TET2, and ASXL1 mutations are detected as age-related clonal hematopoiesis and supposed to be a risk factor for hematological neoplasms. Recent reports on MDS have shown that mutations in genes such as NRAS and FLT3, designated as Type I genes, were significantly associated with leukemic evolution. Another type (Type II) of genes, including RUNX1 and GATA2, has been shown to be related to the progression from low-risk to high-risk MDS. These driver mutations are significantly concomitant during disease progression. Overall, various types of driver mutations are sequentially acquired in MDS, accounting for the heterogeneity of these disorders.

Clinical relevance of mutations in patients with myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms with normal karyotype.

7053 Background: Clinical outcomes of patients with myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) are heterogeneous. Specific mutations and mutation patterns are known to define prognostic groups in normal karyotype acute myeloid leukemia. Whether this is the case in MDS and MDS/MPN remains unknown. Methods: We evaluated 325 previously untreated patients with MDS or MDS/MPN with normal karyotype evaluated from 2012 to 2016. Next generation sequencing (NGS) on whole bone marrow DNA analyzing a panel of 28 or 53 genes was performed at the time of diagnosis. Results: A total of 225 (69%) patients had MDS and 100 (31%) had MDS/MPN including 77 (24%) patients with chronic myelomonocytic leukemia (CMML). Median age was 69 years (31-92). Among patients with MDS, 189 (84%) had lower-risk and 36 (16%) had higher-risk based on IPSS. NGS data was obtained by 53-gene panel in 93 (29%) patients and by 28-gene panel in 232 (71%). A total of 202 (62%) patients had detectable mutations. Median number of mutations was 1 (range 0-6). Detected mutations are detailed in Table 1. A total of 111 (34%) patients, 70 with MDS and 41 with MDS/MPN, received therapy with hypomethylating agents. Median follow up was 12 months (0-167). By univariate analysis, NRAS (HR 3.28, CI 1.25-8.62, p=0.016) and TP53 (HR 4.9, CI 1.44-16.67, p=0.011) predicted for shorter overall survival (OS) among MDS patients. After multivariate analysis including IPSS-R, only TP53retained its impact in OS (HR 5.25, CI 1.44-19.13, p=0.012). Among MDS/MPN patients, no mutation was found to significantly impact OS. Conclusions: With the exception of TP53mutations, no other identified mutation seemed to independently define prognosis of patients with MDS or MDS/MPN with normal karyotype. In view of the high proportion of lower-risk patients, longer follow up is required to better define prognostic impact of mutations in this population. [Table: see text]

Persistence of immunophenotypically aberrant CD34+ myeloid progenitors is frequent in bone marrow of patients with myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms treated with hypomethylating agents

AimsHypomethylating agents (HMAs) exhibit clinical efficacy in patients with myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). This study was performed to assess residual disease status by flow cytometry immunophenotyping (FCI)...

Routine clinical mutation profiling using next generation sequencing and a customized gene panel improves diagnostic precision in myeloid neoplasms.

Microscopic examination of myelodysplastic syndromes (MDS) and myelodysplastic-myeloproliferative neoplasms (MDS/MPN) may be challenging because morphological features can overlap with those of reactive states. Demonstration of clonal hematopoiesis provides a diagnostic clue and has become possible by comprehensive mutation profiling of a number of frequently mutated genes, some of them with large coding regions.To emphasize the potential benefit of NGS in hematopathology we present sequencing results from routinely processed formalin-fixed and paraffin-embedded (FFPE) bone marrow trephines (n = 192). A customized amplicon-based gene panel including 23 genes frequently mutated in myeloid neoplasms was established and implemented. Thereby, 629,691 reads per sample (range 179,847–1,460,412) and a mean coverage of 2,702 (range 707–6,327) could be obtained, which are sufficient for comprehensive mutational profiling. Seven samples failed in sequencing (3.6%). In 185 samples we found in total 269 pathogenic variants (mean 1.4 variants per patient, range 0-5), 125 Patients exhibit at least one pathogenic mutation (67.6%). Variants show allele frequencies ranging from 6.7% up to 95.7%. Most frequently mutated genes were TET2 (28.7%), SRSF2 (19.5%), ASXL1 (8.6%) and U2AF1 (8.1%). The mutation profiling increases the diagnostic precision and adds prognostic information.

Two Novel Distinct Subtypes of Myeloid Neoplasms Molecularly Associated with Histone H3K36 Methylations

Myelodysplastic syndromes (MDS) and related disorders are a heterogeneous group of chronic myeloid neoplasms with a high propensity to acute myeloid leukemia. A cardinal feature of MDS, as revealed by the recent genetic studies, is a high frequency of mutations and copy number variations (CNVs) affecting epigenetic regulators, such as TET2, IDH1/2, DNMT3A, ASXL1, EZH2, and other genes, underscoring a major role of deregulated epigenetic regulation in MDS pathogenesis. Meanwhile, these mutations/deletions have different impacts on the phenotype and the clinical outcome of MDS, suggesting that it should be important to understand the underlying mechanism for abnormal epigenetic regulation for better classification and management of MDS. SETD2 and ASH1L are structurally related proteins that belong to the histone methyltransferase family of proteins commonly engaged in methylation of histone H3K36. Both genes have been reported to undergo frequent somatic mutations and copy number alterations, and also show abnormal gene expression in a variety of non-hematological cancers. Moreover, germline mutation of SETD2 has been implicated in overgrowth syndromes susceptible to various cancers. However, the role of alterations in these genes has not been examined in hematological malignancies including myelodysplasia.In this study, we interrogated somatic mutations and copy number variations, among a total of 1116 cases with MDS and myelodysplastic/myeloproliferative neoplasms (MDS/MPN), who had been analyzed by target deep sequencing (n=944), and single nucleotide polymorphism-array karyotyping (SNP-A) (n=222). Gene expression was analyzed in MDS cases and healthy controls, using publically available gene expression datasets.SETD2 mutations were found in 6 cases, including 2 with nonsense and 4 with missense mutations, and an additional 10 cases had gene deletions spanning 1.8-176 Mb regions commonly affecting the SETD2 locus in chromosome 3p21.31, where SETD2 represented the most frequently deleted gene within the commonly deleted region. SETD2 deletion significantly correlated with reduced SETD2 expression. Moreover, MDS cases showed a significantly higher SETD2 expression than healthy controls. In total, 16 cases had either mutations or deletions of the SETD2 gene, of which 70% (7 out of 10 cases with detailed diagnostic information) were RAEB-1/2 cases. SETD2 -mutated/deleted cases had frequent mutations in TP53 (n=4), SRSF2 (n=3), and ASXL1 (n=3) and showed a significantly poor prognosis compared to those without mutations/deletions (HR=3.82, 95%CI; 1.42-10.32, P=0.004).ASH1L, on the other hand, was mutated and amplified in 7 and 13 cases, respectively, of which a single case carried both mutation and amplification with the mutated allele being selectively amplified. All the mutations were missense variants, of which 3 were clustered between S1201 and S1209. MDS cases showed significantly higher expression of ASH1L compared to healthy controls, suggesting the role of ASH1L overexpression in MDS development. Frequent mutations in TET2 (n=8) and SF3B1 (n=6) were noted among the 19 cases with ASH1L lesions. RAEB-1/2 cases were less frequent (n=11) compared to SETD2-mutated/deleted cases. ASH1L mutations did not significantly affect overall survival compared to ASH1L-intact cases. Gene Set Expression Analysis (Broad Institute) on suppressed SETD2 and accelerated ASH1L demonstrated 2 distinct expression signatures most likely due to the differentially methylated H3K36.We described recurrent mutations and CNVs affecting two histone methyltransferase genes, which are thought to represent novel driver genes in MDS involved in epigenetic regulations. Given that SETD2 overexpression and reduced ASH1L expression are found in as many as 89% of MDS cases, deregulation of both genes might play a more role than expected from the incidence of mutations and CNVs alone. Although commonly involved in histone H3K36 methylation, both methyltransferases have distinct impacts on the pathogenesis and clinical outcome of MDS in terms of the mode of genetic alterations and their functional consequences: SETD2 was frequently affected by truncating mutations and gene deletions, whereas ASH1L underwent gene amplification without no truncating mutations, suggesting different gene targets for both methyltransferases, which should be further clarified through functional studies. DisclosuresAlpermann:MLL Munich Leukemia Laboratory: Employment. Nadarajah:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Shih:Novartis: Research Funding.

Driver somatic mutations identify distinct disease entities within myeloid neoplasms with myelodysplasia

AbstractOur knowledge of the genetic basis of myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) has considerably improved. To define genotype/phenotype relationships of clinical relevance, we studied 308 patients with MDS, MDS/MPN, or acute myeloid leukemia evolving from MDS. Unsupervised statistical analysis, including the World Health Organization classification criteria and somatic mutations, showed that MDS associated with SF3B1-mutation (51 of 245 patients, 20.8%) is a distinct nosologic entity irrespective of current morphologic classification criteria. Conversely, MDS with ring sideroblasts with nonmutated SF3B1 segregated in different clusters with other MDS subtypes. Mutations of genes involved in DNA methylation, splicing factors other than SF3B1, and genes of the RAS pathway and cohesin complex were independently associated with multilineage dysplasia and identified a distinct subset (51 of 245 patients, 20.8%). No recurrent mutation pattern correlated with unilineage dysplasia without ring sideroblasts. Irrespective of driver somatic mutations, a threshold of 5% bone marrow blasts retained a significant discriminant value for identifying cases with clonal evolution. Comutation of TET2 and SRSF2 was highly predictive of a myeloid neoplasm characterized by myelodysplasia and monocytosis, including but not limited to, chronic myelomonocytic leukemia. These results serve as a proof of concept that a molecular classification of myeloid neoplasms is feasible.

Clinical and Molecular Features Of Myeloid Neoplasms Carrying SRSF2 Mutation

BackgroundMutations in genes encoding RNA splicing factors have been recently identified in myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN). SRSF2 mutations have been reported in up to 20% of patients with MDS and in about 40 to 50% of those with chronic myelomonocytic leukemia (CMML). In this latter condition, SRFS2 is the second recurrently mutated gene after TET2, and a significant association between TET2 and SRSF2 mutations has been reported. In MDS, SRSF2 mutations have been associated with a poor prognosis and shortened overall survival and leukemia-free survival, but no clear correlation has been described so far with specific disease phenotype. AimsIn this work, we studied a large and well characterized cohort of MDS and MDS/MPN patients with the aim to describe clinical and molecular features of myeloid neoplasms carrying SRSF2 mutations, to recognize patterns of co-occurring or mutually exclusive mutations, and to identify correlations with disease phenotypes. MethodsMassively parallel pyrosequencing was used to screen coding exons of 111 genes implicated in myeloid malignancies in 267 patients with MDS or MDS/MPN according to WHO criteria, diagnosed at the Department of Hematology, Fondazione IRCCS Policlinico S. Matteo, University of Pavia, Italy. Two-hundred forty five patients were classified as MDS (26 RA; 35 RARS; 69 RCMD; 27 RCMD-RS; 10 MDS with isolated del(5q); 36 RAEB-1 and 42 RAEB-2), and 22 as MDS/MPN (20 CMML and 2 MDS/MPN, unclassifiable, MDS/MPN-U). ResultsHigh-confidence oncogenic mutations were identified in 43 genes, with a median number of 2 mutations per patient (range 0-9).In the MDS/MPN cohort, the most frequent mutations involved SRSF2 (10/22, 45%), TET2 (10/22, 45%) and ASXL1 (5/22, 23%). Seven of 10 (70%) patients with SRSF2 mutation also had a mutation in TET2. SRSF2-mutated patients showed significantly higher hemoglobin level (12.1 vs 9.3 g/dL, P<.001 ) and higher monocyte count (2.42 vs 2.18 x109/L, P=.007) compared to those wild-type for SRSF2. Only 1 of 10 (10%) patients with SRSF2 mutations showed ring sideroblasts in the bone marrow.Among MDS patients, mutations of SRSF2 were observed in 34/245 (14%); significant associations were found with ASXL1 ( 9/34, 26%, P=.027) and IDH 1/2 (9/34, 26%, P<.001). Conversely, mutations of DNMT3A and SF3B1 were mutually exclusive with SRSF2 mutations (0/34, P<.001), while no significant association with TET2 mutations was demonstrated (6/34, 18%, P=ns). A significant association was found between SRSF2 mutations and multilineage dysplasia or excess blasts (2/34 patients with unilineage dysplasia, 16/34 with multilineage dysplasia and 16/34 with RAEB, P=.028). Moreover, SRSF2 mutations were significantly associated with the presence of a variable proportion of bone marrow ring sideroblasts (range 1-68%) (17 of 34 patients, 50%, P=.04). The cases with ring sideroblasts were classified according to WHO criteria as RA or RARS (2), RCMD or RCMD-RS (9), RAEB-1 or RAEB-2 (6). No significantly different mutation pattern was observed in SRSF2-mutated patients with or without ring sideroblasts.Finally, we investigated with an unsupervised approach in our whole cohort of myeloid neoplasms whether mutations of SRSF2 isolated or in association with co-occurring mutations could generate specific disease phenotypes. We found that the association of SRSF2 and TET2 mutations was highly specific for CMML disease phenotype (specificity 97.5%). Interestingly, of the six double mutated patients with a diagnosis of MDS, two showed relative monocytosis at the time of the analysis and two developed an overt CMML during follow-up. When accounting for these cases, the co-occurrence of SRSF2 and TET2 mutations showed specificity and positive predictive value for myelomonocytic phenotype of 99.2% and 84.6% respectively. ConclusionsSRSF2 mutations are significantly associated with multilineage dysplasia and bone marrow ring sideroblasts in MDS patients, whereas the co-occurrence of SRSF2 and TET2 mutations is highly specific for the myelomonocytic phenotype of CMML. These data suggest that SRSF2 mutation is associated per se with a specific phenotype (ring sideroblasts and multilineage dysplasia), but also that its phenotypic impact may be modulated through interaction with other mutant genes like TET2. Disclosures:No relevant conflicts of interest to declare.

Incidence, survival and prevalence of myeloid malignancies in Europe

BackgroundThe Surveillance of Rare Cancers in Europe (RARECARE) project aims at increasing knowledge of rare cancers in Europe. This manuscript describes the epidemiology of myeloid malignancies (MMs), taking into account the morphological characterisation of these tumours. MethodsWe used data gathered by RARECARE on cancer patients diagnosed from 1995 to 2002 and archived in 64 European population-based cancer registries, followed up to 31st December 2003 or later. ResultsThe overall annual crude incidence of MMs was 8.6 per 100,000. Acute myeloid leukaemia (AML) and myeloproliferative neoplasms (MPN) were most common, with incidence rates of 3.7 and 3.1 per 100,000year respectively, followed by 1.8 for myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MD/MPN) and 0.1 for histiocytic and dendritic cell neoplasms (HDCN). The 5-year relative survival rate ranged from 18% for chronic myelomonocytic leukaemia, 19% for AML, 29% for MDS and 44% for chronic myeloid leukaemia to relatively favourable rates for MPN (62%) and HDCN (83%). Total number of new cases of MMs in the EU27 is estimated at 43,000 annually, total number of prevalent cases (1st January 2008) at 189,000 cases. ConclusionMMs form a large variety of rare entities with specific characteristics. Collection of detailed information (immunophenotype, genetic abnormalities, molecular data and clinical data) and an up-to-date classification system is essential for their surveillance, especially now that more and more targeted therapies are being introduced.

Novel splicing-factor mutations in juvenile myelomonocytic leukemia

Novel splicing-factor mutations in juvenile myelomonocytic leukemia

Changed concepts and definitions of myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS) and myelodysplastic/myeloproliferative neoplasms (MDS/MPN) in the updated 2008 WHO classification

The purpose of this overview is to discuss the changes in the 2008 WHO classification of myeloid neoplasms, with exclusion of acute myeloid leukaemia. Specific mutations or rearrangements leading to constitutive activation of growth factor receptors or cytoplasmic tyrosine kinases are now recognised as recurrent genetic events characterising the group of myeloproliferative neoplasms (MPN). A newly introduced subgroup consists of patients with persistent eosinophilia and myeloid or lymphoid proliferations harbouring specific genetic changes involving platelet-derived growth factor receptors alpha and beta (PDGFRA and PDGFRB) or fibroblast growth factor receptor 1 (FGFR1). The clinical relevance of recognising myeloid neoplasms with aberrant tyrosine kinase activity is based in novel treatment options with tyrosine kinase inhibitors. The myelodysplastic syndromes (MDS) without increased blasts are further divided into subtypes of refractory cytopaenias with unilineage dysplasia. A new provisional entity is refractory cytopaenia of childhood. Down syndrome- and therapy-related myeloid neoplasms, including MDS, were moved to the section of acute myeloid leukaemia and related precursor neoplasms.