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PROVIDER: PRJNA116639 | ENA |
REPOSITORIES: ENA
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Project description:Mutations in the TET2 gene are frequent in myeloid disease, although their biological and prognostic significance remains unclear. We analyzed 355 patients with myelodysplastic syndromes using ‘Next-Generation’ sequencing (NGS) for TET2 aberrations; 91 of whom were also subjected to SNP6 array karyotyping. Seventy-one TET2 mutations, with a relative mutation abundance (RMA) ≥10%, were identified in 39 of 320 (12%) MDS and 16 of 35 (46%) CMML patients (p<0.001). Interestingly, 4 patients had multiple mutations likely to exist as independent clones or on alternate alleles, suggestive of clonal evolution. ‘Deeper’ sequencing of 96 patient samples identified 4 additional mutations (RMA 3%-6.3%). Importantly, TET2 mutant clones were also found in T cells in addition to CD34+ and total bone-marrow cells (23.5%, 38.5% and 43% RMA respectively). Only 20% of the TET2-mutated patients showed loss of heterozygosity at the TET2 locus. There was no difference in the frequency of genome-wide aberrations, TET2 expression or the JAK2V617F 46/1 haplotype between TET2-mutated and non-mutated patients. There was no significant prognostic association between TET2 mutations and WHO subtypes, IPSS score, cytogenetic status, or transformation to AML. On multivariate analysis, age (>50yrs) was associated with a higher incidence of TET2 mutation (p=0.02). Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from bone marrow or peripheral blood samples. Copy number and acquired UPD analysis of Affymetrix SNP 6.0 arrays was performed for 91 cases with Myelodysplastic syndromes.
2010-07-30 | E-GEOD-23300 | biostudies-arrayexpress
Project description:Somatic mutations and CNVs in myelodysplastic syndromes
| PRJNA317246 | ENA
Project description:Myelodysplastic syndromes (MDS) represent a heterogeneous group of neoplastic hematopoietic disorders. Several recurrent chromosomal aberrations have been associated with MDS, but the genes affected have remained largely unknown. To identify relevant genetic lesions involved in the pathogenesis of MDS, we performed SNP-array-based genomic profiling and genomic sequencing in 102 patients. We identified acquired deletions, missense and nonsense mutations in a new gene, TET2, in 26% of MDS patients. Using allele-specific assays, TET2 mutations were shown to be present in the majority of the myeloid cells (56-100%, median 96%). In addition, the mutations were encountered in various lineages of differentiation including CD34+ progenitor cells, suggesting that TET2 mutations occur early during disease evolution. In healthy tissues TET2 expression was shown to be elevated in hematopoietic cells with highest expression in granulocytes, in line with a function in myelopoiesis. We conclude that TET2 is the most frequently mutated gene in MDS known so far.
2009-05-28 | GSE15688 | GEO
Project description:TET2 is a close relative of TET1, an enzyme that converts 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. The gene encoding TET2 resides at chromosome 4q24, in a region showing recurrent microdeletions and copy-neutral loss of heterozygosity (CN-LOH) in patients with diverse myeloid malignancies. Somatic TET2 mutations are frequently observed in myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), MDS/MPN overlap syndromes including chronic myelomonocytic leukaemia (CMML), acute myeloid leukaemias (AML) and secondary AML (sAML). We show here that TET2 mutations associated with myeloid malignancies compromise catalytic activity. Bone marrow samples from patients with TET2 mutations displayed uniformly low levels of 5hmC in genomic DNA compared to bone marrow samples from healthy controls. Moreover, small hairpin RNA (shRNA)-mediated depletion of Tet2 in mouse haematopoietic precursors skewed their differentiation towards monocyte/macrophage lineages in culture. There was no significant difference in DNA methylation between bone marrow samples from patients with high 5hmC versus healthy controls, but samples from patients with low 5hmC showed hypomethylation relative to controls at the majority of differentially methylated CpG sites. Our results demonstrate that Tet2 is important for normal myelopoiesis, and suggest that disruption of TET2 enzymatic activity favours myeloid tumorigenesis. Measurement of 5hmC levels in myeloid malignancies may prove valuable as a diagnostic and prognostic tool, to tailor therapies and assess responses to anticancer drugs. Genome wide DNA methylation profiling of patients samples with various myeloid malignancies and diffrential levels of 5hmC.The Illumina Infinium 27k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 27,000 CpGs in bone marrow samples and occasionally peripheral blood samples. Samples included 28 control healthy bone marrows, 29 patients samples with low 5hmC levels (7 patients with wild-type TET2 and 22 mutant TET2) and 24 with high levels of 5hmC (22 with wild-type TET2 and 2 mutant TET2). Bisulphite converted DNA from 81 samples was hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2
2010-12-11 | E-GEOD-25706 | biostudies-arrayexpress
Project description:Mutations in the TET2 gene are frequent in myeloid disease, although their biological and prognostic significance remains unclear. We analyzed 355 patients with myelodysplastic syndromes using ‘Next-Generation’ sequencing (NGS) for TET2 aberrations; 91 of whom were also subjected to SNP6 array karyotyping. Seventy-one TET2 mutations, with a relative mutation abundance (RMA) ≥10%, were identified in 39 of 320 (12%) MDS and 16 of 35 (46%) CMML patients (p<0.001). Interestingly, 4 patients had multiple mutations likely to exist as independent clones or on alternate alleles, suggestive of clonal evolution. ‘Deeper’ sequencing of 96 patient samples identified 4 additional mutations (RMA 3%-6.3%). Importantly, TET2 mutant clones were also found in T cells in addition to CD34+ and total bone-marrow cells (23.5%, 38.5% and 43% RMA respectively). Only 20% of the TET2-mutated patients showed loss of heterozygosity at the TET2 locus. There was no difference in the frequency of genome-wide aberrations, TET2 expression or the JAK2V617F 46/1 haplotype between TET2-mutated and non-mutated patients. There was no significant prognostic association between TET2 mutations and WHO subtypes, IPSS score, cytogenetic status, or transformation to AML. On multivariate analysis, age (>50yrs) was associated with a higher incidence of TET2 mutation (p=0.02).
2010-07-30 | GSE23300 | GEO
Project description:Acquired spliceosome gene mutations are among the most common genetic alterations in myelodysplastic syndromes (MDS). Here we present evidence that H2AFY(macroH2A1), a histone H2A variant, is a functional target that is alternatively spliced by mutant U2AF1(S34F), a spliceosome gene. Expression of H2AFY1.1, a H2AFY splice-isoform that is reduced by U2AF1(S34F) expression, rescues the reduction in B-cells observed in U2AF1(S34F) mice. Human MDS samples with U2AF1 mutations have a similar reduction in B-cells. Collectively, our data suggest that altered splicing of H2AFY contributes to MDS pathogenesis.
2021-08-31 | GSE125118 | GEO
Project description:Gene expression profiling in myelodysplastic syndromes
| PRJNA143949 | ENA
Project description:Affymetrix SNP6.0 microarray data - Myelodysplastic syndromes
| PRJNA131331 | ENA
Project description:TET2 is a close relative of TET1, an enzyme that converts 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. The gene encoding TET2 resides at chromosome 4q24, in a region showing recurrent microdeletions and copy-neutral loss of heterozygosity (CN-LOH) in patients with diverse myeloid malignancies. Somatic TET2 mutations are frequently observed in myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), MDS/MPN overlap syndromes including chronic myelomonocytic leukaemia (CMML), acute myeloid leukaemias (AML) and secondary AML (sAML). We show here that TET2 mutations associated with myeloid malignancies compromise catalytic activity. Bone marrow samples from patients with TET2 mutations displayed uniformly low levels of 5hmC in genomic DNA compared to bone marrow samples from healthy controls. Moreover, small hairpin RNA (shRNA)-mediated depletion of Tet2 in mouse haematopoietic precursors skewed their differentiation towards monocyte/macrophage lineages in culture. There was no significant difference in DNA methylation between bone marrow samples from patients with high 5hmC versus healthy controls, but samples from patients with low 5hmC showed hypomethylation relative to controls at the majority of differentially methylated CpG sites. Our results demonstrate that Tet2 is important for normal myelopoiesis, and suggest that disruption of TET2 enzymatic activity favours myeloid tumorigenesis. Measurement of 5hmC levels in myeloid malignancies may prove valuable as a diagnostic and prognostic tool, to tailor therapies and assess responses to anticancer drugs.
2010-12-11 | GSE25706 | GEO