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O-025 GATA2 mutations in pediatric myelodysplastic syndrome and bone marrow failure disorders
S20
Oral Presentations – 12th International Symposium on Myelodysplastic Syndromes / Leukemia Research 37 S1 (2013) S1–S117
D. Neuberg 2 , B.L. Ebert 8 . 1 Hematology/Oncology, University of California San Diego, San Diego, USA; 2 Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, USA; 3 Cancer Genome Computational Analysis, Broad Institute, Boston, USA; 4 Molecular and Human Genetics, Baylor University, Houston, USA; 5 Medical Oncology Leukemia, Dana-Farber Cancer Institute, Boston, USA; 6 School of Medicine, University of California San Diego, San Diego, USA; 7 Leukemia, MD Anderson Cancer Center, Houston, USA; 8 Hematology, Brigham and Women’s Hospital, Boston, USA Background: Azacitidine and decitabine are active therapies for patients with myelodysplastic syndromes (MDS), but their overall response rate is only in the 50% range. Reliable biomarkers that predict response to these hypomethylating agents would help physicians select treatments options for their patients. Somatic mutations are common in MDS and can carry prognostic significance that is independent of the International Prognostic Scoring System (IPSS). However, their association with therapeutic response is largely uncharacterized. One study noted that mutations in TET2 appear to predict response to azacitidine, but other potentially confounding mutations were not explored. Broader genetic profiling of MDS patients may identify patterns of mutations more strongly associated with response. Purpose: We hypothesize that abnormalities in recurrently mutated genes may predict response to hypomethylating agents in patients with MDS. Materials and Methods: Tumor sample DNA was sequenced from 213 MDS patients prior to treatment with azacitidine (n=42), decitabine (n=144), or decitabine plus another agent (n=27). Responses were assessed using the revised International Working Group Response Criteria for MDS. The coding regions of 74 myeloid malignancy related genes were enriched by pooled hybrid capture and sequenced on the Illumina platform. Variants were identified using the analysis pipeline at the Broad Institute. Abnormalities present in databases of normal variants (dbSNP 132 or ESP6500) at a population frequency of ≥1% were discarded. Remaining variants were considered candidate somatic mutations. Results: Candidate mutations were identified in over 90% of samples. The most frequently mutated genes were ASXL1 (46%), TET2 (27%), RUNX1 (20%), and TP53 (18%). The overall response rate was 47% and did not differ between sites or choice of therapy. In multivariable analysis, CBL mutations (7%) were associated with a lower response rate (odds ratio [OR] 0.13, 95% CI 0.03-0.64) and NRAS mutations (11%) with a higher response rate (OR 2.67, 95% 1.03-6.93). Patients with mutant TET2 and wildtype ASXL1 also demonstrated an increased response rate (OR 2.37, 95% CI 1.00-5.58). When low abundance mutations were excluded (frequency <10%), TET2 mutations were the only independent genetic predictor of response (OR 1.99, 95% CI 1.05-3.80), suggesting a threshold at which these mutations become clinically relevant. Survival data were available for 146 patients. Mutations of TP53 and PTPN11 were each independently associated with shorter overall survival. Conclusions: Quantitative mutation profiling can identify MDS patients with differences in response rates to hypomethylating agents and in overall survival. Higher frequency TET2 mutations were most strongly associated with response, particularly in ASXL1 wildtype patients.
Children’s Hospital, Boston, USA; 2 Department of Pathology, Boston Children’s Hospital, Boston, USA; 3 Department of Genetics, Boston Children’s Hospital, Boston, USA Background: Inherited bone marrow failure syndromes (IBMFS), idiopathic aplastic anemia (AA), and myelodysplastic syndromes (MDS) represent a spectrum of bone marrow failure (BMF) conditions for which the underlying genetics and pathophysiology are still poorly understood. Heterozygous germline mutations in GATA2 cause three distinct entities: familial MDS/AML, Emberger syndrome and MonoMac syndrome, each of which exhibits great clinical heterogeneity. Introduction: The Pediatric MDS and BMF Registry was established in 2010 to characterize clinical and histopathologic phenotypes and investigate the molecular basis of these disorders. Purpose: To determine the prevalence of GATA2 mutations in pediatric patients with MDS and BMF and characterize their clinical and histopathologic phenotypes. Materials and Methods: Sanger sequencing of GATA2 was performed on 4 families with MDS as well as 90 patients with apparently sporadic pediatric MDS, AA or an unclassified BMF disorder. IBMFS were ruled out by molecular testing. Rigorous phenotypic analysis included detailed clinical and laboratory data, family history and standardized centralized pathology. Whole exome sequencing was performed on a subset of patients to evaluate secondary somatic events and clonal evolution. Results: We identified pathogenic GATA2 mutations in a total of 12 individuals, including 6 patients and 2 first-degree relatives from 4 kindreds and 4 sporadic cases. Most mutations clustered in zinc finger 2. Previously identified mutations including N371K and R396Q as well as novel mutations were identified. The median age at diagnosis was 15 years. There was strong male predominance (n=10). The clinico-pathologic diagnoses were RAEB/AML (n=3), refractory cytopenia of (n=7) and other (n=2). Two of four families presented with features of Emberger syndrome. One individual presented with characteristic features of MonoMac Syndrome. Other associated pathologies included severe gastrointestinal bleeding (n=2), severe polyneuropathy (n=1) and other cancers (n=1). A morphologically distinctive megakaryocytic dysplasia was a characteristic finding on histopathology. Monosomy 7 and trisomy 8 were the most common acquired cytogenetic abnormalities. Secondary somatic mutations in ASXL1 were identified in several patients. All patients except one underwent HSCT and all but one are alive. Conclusions: GATA2 mutations occur at a higher frequency than previously anticipated in pediatric MDS, and BMF, often occur sporadically and are associated with monosomy 7. While the clinical presentation is heterogeneous, the histopathologic features are unique. Somatic genetic alterations likely play a role in clonal evolution. Given its implications for treatment decisions and donor selection, GATA2 mutation screening should be performed on all pediatric patients with AML, MDS, AA, and BMF disorders as well as potential related HSCT donors.
O-026 Genome-wide methylation profiling by MCIp-Seq reveals aberrant DNA methylation patterns in childhood MDS with GATA2-deficiency
O-025 GATA2 mutations in pediatric myelodysplastic syndrome and bone marrow failure disorders
S. Pohl 1 , D. Heudobler 1 , C. Gebhard 1 , S. Hirabayashi 2 , C. Niemeyer 2 , M. Wlodarski 2 , M. Rehli 1 . 1 Department of Hematology and Oncology, University Hospital Regensburg, Regensburg, Germany; 2 Department of Pediatric Hematology and Oncology, University Hospital Freiburg, Freiburg, Germany
I. Hofmann 1 , J. Krasker 1 , D. Campagna 2 , D. Kierstead 2 , K. Schmitz-Abe 3 , K. Markianos 3 , M. Lee 1 , C. Sieff 1 , D.A. Williams 1 , M.D. Fleming 2 . 1 Division of Pediatric Hematology/Oncology, Boston
Background: Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic disorders characterized by bone marrow failure, clonal and ineffective hematopoiesis as well as
Oral Presentations – 12th International Symposium on Myelodysplastic Syndromes / Leukemia Research 37 S1 (2013) S1–S117
D. Neuberg 2 , B.L. Ebert 8 . 1 Hematology/Oncology, University of California San Diego, San Diego, USA; 2 Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, USA; 3 Cancer Genome Computational Analysis, Broad Institute, Boston, USA; 4 Molecular and Human Genetics, Baylor University, Houston, USA; 5 Medical Oncology Leukemia, Dana-Farber Cancer Institute, Boston, USA; 6 School of Medicine, University of California San Diego, San Diego, USA; 7 Leukemia, MD Anderson Cancer Center, Houston, USA; 8 Hematology, Brigham and Women’s Hospital, Boston, USA Background: Azacitidine and decitabine are active therapies for patients with myelodysplastic syndromes (MDS), but their overall response rate is only in the 50% range. Reliable biomarkers that predict response to these hypomethylating agents would help physicians select treatments options for their patients. Somatic mutations are common in MDS and can carry prognostic significance that is independent of the International Prognostic Scoring System (IPSS). However, their association with therapeutic response is largely uncharacterized. One study noted that mutations in TET2 appear to predict response to azacitidine, but other potentially confounding mutations were not explored. Broader genetic profiling of MDS patients may identify patterns of mutations more strongly associated with response. Purpose: We hypothesize that abnormalities in recurrently mutated genes may predict response to hypomethylating agents in patients with MDS. Materials and Methods: Tumor sample DNA was sequenced from 213 MDS patients prior to treatment with azacitidine (n=42), decitabine (n=144), or decitabine plus another agent (n=27). Responses were assessed using the revised International Working Group Response Criteria for MDS. The coding regions of 74 myeloid malignancy related genes were enriched by pooled hybrid capture and sequenced on the Illumina platform. Variants were identified using the analysis pipeline at the Broad Institute. Abnormalities present in databases of normal variants (dbSNP 132 or ESP6500) at a population frequency of ≥1% were discarded. Remaining variants were considered candidate somatic mutations. Results: Candidate mutations were identified in over 90% of samples. The most frequently mutated genes were ASXL1 (46%), TET2 (27%), RUNX1 (20%), and TP53 (18%). The overall response rate was 47% and did not differ between sites or choice of therapy. In multivariable analysis, CBL mutations (7%) were associated with a lower response rate (odds ratio [OR] 0.13, 95% CI 0.03-0.64) and NRAS mutations (11%) with a higher response rate (OR 2.67, 95% 1.03-6.93). Patients with mutant TET2 and wildtype ASXL1 also demonstrated an increased response rate (OR 2.37, 95% CI 1.00-5.58). When low abundance mutations were excluded (frequency <10%), TET2 mutations were the only independent genetic predictor of response (OR 1.99, 95% CI 1.05-3.80), suggesting a threshold at which these mutations become clinically relevant. Survival data were available for 146 patients. Mutations of TP53 and PTPN11 were each independently associated with shorter overall survival. Conclusions: Quantitative mutation profiling can identify MDS patients with differences in response rates to hypomethylating agents and in overall survival. Higher frequency TET2 mutations were most strongly associated with response, particularly in ASXL1 wildtype patients.
Children’s Hospital, Boston, USA; 2 Department of Pathology, Boston Children’s Hospital, Boston, USA; 3 Department of Genetics, Boston Children’s Hospital, Boston, USA Background: Inherited bone marrow failure syndromes (IBMFS), idiopathic aplastic anemia (AA), and myelodysplastic syndromes (MDS) represent a spectrum of bone marrow failure (BMF) conditions for which the underlying genetics and pathophysiology are still poorly understood. Heterozygous germline mutations in GATA2 cause three distinct entities: familial MDS/AML, Emberger syndrome and MonoMac syndrome, each of which exhibits great clinical heterogeneity. Introduction: The Pediatric MDS and BMF Registry was established in 2010 to characterize clinical and histopathologic phenotypes and investigate the molecular basis of these disorders. Purpose: To determine the prevalence of GATA2 mutations in pediatric patients with MDS and BMF and characterize their clinical and histopathologic phenotypes. Materials and Methods: Sanger sequencing of GATA2 was performed on 4 families with MDS as well as 90 patients with apparently sporadic pediatric MDS, AA or an unclassified BMF disorder. IBMFS were ruled out by molecular testing. Rigorous phenotypic analysis included detailed clinical and laboratory data, family history and standardized centralized pathology. Whole exome sequencing was performed on a subset of patients to evaluate secondary somatic events and clonal evolution. Results: We identified pathogenic GATA2 mutations in a total of 12 individuals, including 6 patients and 2 first-degree relatives from 4 kindreds and 4 sporadic cases. Most mutations clustered in zinc finger 2. Previously identified mutations including N371K and R396Q as well as novel mutations were identified. The median age at diagnosis was 15 years. There was strong male predominance (n=10). The clinico-pathologic diagnoses were RAEB/AML (n=3), refractory cytopenia of (n=7) and other (n=2). Two of four families presented with features of Emberger syndrome. One individual presented with characteristic features of MonoMac Syndrome. Other associated pathologies included severe gastrointestinal bleeding (n=2), severe polyneuropathy (n=1) and other cancers (n=1). A morphologically distinctive megakaryocytic dysplasia was a characteristic finding on histopathology. Monosomy 7 and trisomy 8 were the most common acquired cytogenetic abnormalities. Secondary somatic mutations in ASXL1 were identified in several patients. All patients except one underwent HSCT and all but one are alive. Conclusions: GATA2 mutations occur at a higher frequency than previously anticipated in pediatric MDS, and BMF, often occur sporadically and are associated with monosomy 7. While the clinical presentation is heterogeneous, the histopathologic features are unique. Somatic genetic alterations likely play a role in clonal evolution. Given its implications for treatment decisions and donor selection, GATA2 mutation screening should be performed on all pediatric patients with AML, MDS, AA, and BMF disorders as well as potential related HSCT donors.
O-026 Genome-wide methylation profiling by MCIp-Seq reveals aberrant DNA methylation patterns in childhood MDS with GATA2-deficiency
O-025 GATA2 mutations in pediatric myelodysplastic syndrome and bone marrow failure disorders
S. Pohl 1 , D. Heudobler 1 , C. Gebhard 1 , S. Hirabayashi 2 , C. Niemeyer 2 , M. Wlodarski 2 , M. Rehli 1 . 1 Department of Hematology and Oncology, University Hospital Regensburg, Regensburg, Germany; 2 Department of Pediatric Hematology and Oncology, University Hospital Freiburg, Freiburg, Germany
I. Hofmann 1 , J. Krasker 1 , D. Campagna 2 , D. Kierstead 2 , K. Schmitz-Abe 3 , K. Markianos 3 , M. Lee 1 , C. Sieff 1 , D.A. Williams 1 , M.D. Fleming 2 . 1 Division of Pediatric Hematology/Oncology, Boston
Background: Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic disorders characterized by bone marrow failure, clonal and ineffective hematopoiesis as well as