Unknown,Transcriptomics,Genomics,Proteomics

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SNP data of MPD/MPN samples

ABSTRACT: Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) including polycythemia vera, essential thrombocythemia and primary myelofibrosis show an inherent tendency for transformation into leukemia (MPN-blast phase), which is hypothesized to be accompanied by acquisition of additional genomic lesions. We, therefore, examined chromosomal abnormalities by high-resolution single-nucleotide polymorphism (SNP) array in 88 MPN patients, as well as 71 cases with MPN-blast phase, and correlated these findings with their clinical parameters. Frequent genomic alterations were found in MPN after leukemic transformation with up to 3-fold more genomic changes per sample compared to samples in chronic phase (p<0.001). We identified commonly altered regions involved in disease progression including established targets (ETV6, TP53 and RUNX1), as well as new candidate genes on 7q, 16q, 19p and 21q. Moreover, trisomy 8 or amplification of 8q24 (MYC) was almost exclusively detected in JAK2V617F(-) cases with MPN-blast phase. Remarkably, copy-number neutral-loss of heterozygosity (CNN-LOH) on either 7q or 9p including homozygous JAK2V617F was related to decreased survival after leukemic transformation (p=0.01 and p=0.016, respectively). Our high density SNP-array analysis of MPN genomes in the chronic compared to leukemic stage identified novel target genes and provided prognostic insights associated with the evolution to leukemia. Keywords: SNP-chip To identify oncogenic lesions in MPD, we performed a genome-wide analysis of primary MPD samples using high-density SNP arrays (Affymetrix GeneChip).

ORGANISM(S): Homo sapiens

SUBMITTER: Ruben Mesa

PROVIDER: E-GEOD-19647 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Myelodysplastic syndromes (MDS) are clonal disorders of hematopoietic progenitors characterized by ineffective hematopoiesis and high propensity to leukemias. Although a number of gene targets have been identified, in many MDS cases, particular genetic targets are unknown. In this study, we performed genome-wide profiling of copy number (CN) abnormalities and allelic imbalances in MDS genomes in order to clarify the distribution of LOH (loss of heterozygosity) and identify their target genes. We analyzed a total of 171MDS and MDS/MPD specimens, including 7 RA/RARS, 23 RCMD/RCMD-RS, 6 5q-syndrome, 30 RAEB-1, 40 RAEB-2, 4 therapy related-MDS/AML, 5 MDSu, 17 CMML-1, 16 CMML-2, 24 overt AML, using high-density SNP arrays. The data were analyzed by CNAG/AsCNAR software we specifically developed for allele-specific CN analysis and sensitive LOH detection. MDS showed characteristic CN profiles in SNP array analysis. Of particular interest is the finding of high frequency of CN-neutral LOH (Uniparental disomy,UPD), which were observed in 51 of 171 (30%) MDS cases. They preferentially involved 1p, 1q, 4q, 7q, 11q, 17p and other chromosomal segments, which were associated with homozygous mutations of both loss-of-function mutations and gain-of function mutations of tumor suppressor genes and cellular oncogenes, including TP53 (17p UPD), AML1/RUNX1 (21q UPD), Nras and cMPL (1p UPD), JAK-2 (9p UPD), and FLT3 (13q UPD). Next we tried to identify a new gene target in 11q UPD, which was most common UPD region in this study and many of these cases were CMML with a normal karyotype. The minimum 11q UPD segment is about 2Mb which existed in 11q23. We sequenced coding exons of c-cbl and detected homozygous mutations in 8 of 9 MDS cases with 11q UPD (CMML= 5, RAEB= 3, overt leukemia= 1), but very rare in cases without 11q UPD (1/162), demonstrating that the mutation is tightly linked to 11q UPD. These mutations were 8 point mutations and 1 micro-deletion, they were accumulated in the linker or RING domain. These c-cbl mutants can transform NIH3T3 in a dominant manner and these mutants are phosphorylated and activate PI3K-Akt pathway. To investigate the functions of these mutants in hematopoietic cells, we introduced these mutants into c-kit(+)Sca1(+)Lin(-) murine bone marrow cells, it prolonged replating capacity of these hematopoietic progenitors. Keywords: SNP-chip To identify oncogenic lesions in MDS, we performed a genome-wide analysis of primary MDS samples using high-density SNP arrays (Affymetrix GeneChip).

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SNP data of MPD/MPN samples

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