Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

High-resolution, genome-wide analysis of human medulloblastoma samples by array-Comparative Genomic Hybridization (aCGH)

ABSTRACT: Medulloblastoma (MB) is the most common pediatric brain tumor and is an aggressive neoplasia arising in the cerebellum. MB includes four major histological subsets commonly subdivided in: classic, desmoplastic, anaplastic or large-cell, and nodular. The current patients risk stratification is based on the age at diagnosis (> or < 3 years at diagnosis), the extent of residual tumor mass post-operative, and disease dissemination. An average risk is assigned to patients older than 3 years of age with minimal or no tumor residual. These patients are more than 60% of overall MBs and have an overall survival between 50-70% at 5 years. It is widely accepted that tumor aggressiveness and progression depend on genetic abnormalities. We performed the genome-wide study, focused on classic MB belonging to pediatric patients at standard risk. We analyzed 31 MB samples using high resolution oligonucleotide Human Genome CGH 244K (Agilent Technologies). The present study may help to identify novel molecular prognostic markers useful to refining current criteria of patientsM-BM-4 relapse risk estimation in this subgroup of patients. We analyzed 31 samples of classic medulloblastoma from patients older than 3 years of age at diagnosis

ORGANISM(S): Homo sapiens

SUBMITTER: simona coco

PROVIDER: E-GEOD-23005 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Chromosome 9q and 16q loss identified by genome-wide pooled-analysis are associated with tumor aggressiveness in patients with classic medulloblastoma.

Coco Simona S Valdora Francesca F Bonassi Stefano S Scaruffi Paola P Stigliani Sara S Oberthuer André A Berthold Frank F Andolfo Immacolata I Servidei Tiziana T Riccardi Riccardo R Basso Eleonora E Iolascon Achille A Tonini Gian Paolo GP

Omics : a journal of integrative biology 20110224 5

Medulloblastoma (MB) is one of the most aggressive pediatric brain tumor. We report genome-wide pooled-analysis of classic MB variant of patients over 3 years of age at diagnosis. We combined array comparative genomic hybridization (aCGH) results from experimental analysis (31 cases) with two public databases (55 cases) in a final evaluation of 86 MBs. The most common chromosome structural aberrations were gains of 17q (45.3%), 1q (22.1%), and losses of 8p (15.1%), 10q (19.8%), 17p (37.2%), and ...[more]

PMID: 21348762

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Project description:Less than 30% of children with high-risk (HR) metastatic neuroblastoma (NB) show a long survival (Pearson 2000). In order to identify novel molecular prognostic markers useful to better predict patientsM-bM-^@M-^Y relapse risk estimation, we performed genome- and/or transcriptome-wide analyses of 129 stage 4 HR-NBs. This is the largest study for this NB subtype. Children older than 1 year of age at diagnosis were categorized as M-bM-^@M-^\short-survivorsM-bM-^@M-^] (dead of disease within 5 years from diagnosis) and M-bM-^@M-^\long-survivorsM-bM-^@M-^] (alive with an overall survival time > 5 years). A significant correlation of patient survival with the presence of small number of segmental copy number aberrations (CNA < 3) was observed. Thus, within the group of stage 4 HR-NBs, we identified a specific subgroup of patients (those with highest number of CNA) that have a higher risk of progression/recurrence. The complex genomic pattern is an independent prognostic marker, since MYCN oncogene amplification only affects the predictive value of single CNA (i.e., 1p loss, 17q gain). Integrative analysis of genomic and expression signatures demonstrated that fatal outcome is associated with loss of cell cycle control and with progression of tumor due to deregulation of Rho GTPase signaling and genes related to cell motility. Tumors with MYCN amplification showed a lower chromosome instability compared to MYCN-single copy NBs (P=0.0008), dominated by 17q gain and 1p loss. Moreover, our results suggest that the MYCN amplification mainly drives the disruption of neuronal differentiation and the reduction of cell adhesion process involved in tumor invasion and metastasis. For array-CGH profiling, we analyzed 91 samples of metastatic neuroblastomas. All patients were classified as stage 4 and they were older than 1 year of age at time of diagnosis. Regarding the clinical course, 46 were short-survivors (dead of disease within 60 months from diagnosis. Deaths due to toxicity were censored) and 45 were long-survivors (alive with an overall survival time > 60 months). This submission consists of 22 new samples and 69 other cases previously deposited in GEO under Series accessions GSE14109 and GSE25771.

Project description:Neuroblastoma (NB) is an aggressive tumor that affects both infants and children. The disease outcome is greatly influenced by age of patient, stage, chromosome copy number aberrations (CNAs) and gene expression abnormalities. We analyzed, by microarray technology, genome and transcriptome of 3 groups of tumors of patients with metastatic disease: G1, stage 4S and MYCN single copy; G2, stage 4 younger than 18 months of age, MYCN single copy with no disease progression and G3, stage 4, older than 19 months, with unfavorable outcome. We found an accumulation of structural copy number aberrations (CNAs) in G3 whereas G1 tumors had mostly numerical (N) CNAs and G2 showed an intermediate behavior. Pair wise comparisons demonstrated that the average of N CNAs significantly decreased from G1 to G2 to G3 (9.6 G1 < 7.2 G2 < 3.6 G3); in contrast S CNAs significantly increased in G3 (0.7 G1 < 3.7 G2 < 7.0 G3). Interestingly, we observed several intra-chromosomal rearrangements in G3 tumors on chromosomes not usually involved in NB. Excluding MYCN amplified tumors by G3 we found a high frequency of S CNAs in this group. Gene expression analysis showed a deregulation of downstream genes of Ras and Rho signaling pathway among the 3 groups. It has been also observed a progressive switch off of development and adhesion genes and a switch on of cell cycle genes from G1 to G2 to G3. Moreover, the telemorase genes were significantly expressed in G3 with respect to remaining groups. Present data show an accumulation of S CNAs from stage 4S to 4. The deregulation of genes Rho/Ras pathway may explain the increase of tumor aggressiveness from G1 to G2 to G3. The increase of cell cycle and telomerase genes expression associated with G3 would provide unlimited replicative potential for these tumors and may be responsible for accumulation of S CNAs. Finally, we can argue that accumulation of structural aberrations and gene deregulation is age-dependent and it is associated with a more aggressive tumor phenotype. We analyzed 133 samples of metastatic neuroblastoma from patients divided into three groups: G1 49 patients stage 4S and MYCN single copy; G2 37 patients stage 4 younger than 18 months of age at diagnosis, MYCN single copy with no disease progression; G3 47 patients stage 4 older than 19 months of age at diagnosis, with unfavorable outcome.

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Dataset Information

High-resolution, genome-wide analysis of human medulloblastoma samples by array-Comparative Genomic Hybridization (aCGH)

Publications

Chromosome 9q and 16q loss identified by genome-wide pooled-analysis are associated with tumor aggressiveness in patients with classic medulloblastoma.

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