Acute Lymphoblastic Leukemia (ALL) in infants (<1 year) is characterized by a poor prognosis and a high incidence of MLL translocations. Several studies demonstrated the unique gene expression profile associated with MLL-rearranged ALL, but generally small cohorts were analyzed as uniform patient groups regardless of the type of MLL translocation, while the analysis of translocation-negative infant ALL remained unacknowledged.
Gene expression profiling-based dissection of MLL translocated and MLL germline acute lymphoblastic leukemia in infants.
Sex, Age, Specimen part
View SamplesFicolled AML-M0 sample gene expression profiles on Affymetrix HGU133Plus2.0 GeneChips. Acute myeloid leukemia (AML) classified as FAB-M0 is defined as a subtype with minimally differentiated morphology. Here we investigated by gene expression (GEP) profiling whether AML-M0 cases should be considered as one or more unique molecular subgroups that discriminates them from other AML patients. By applying GEP and subsequent unsupervised analysis of 35 AML-M0 samples and 253 previously reported AML cases, we demonstrate that AML-M0 cases express a unique signature. Hematological transcription regulators such as CEBPA, CEBPD, PU.1 and ETV6 and the differentiation associated gene MPO appeared strongly down-regulated, in line with the very primitive state of this type of leukemia. Moreover, AML M0 cases appeared to have a strong positive correlation with a previously defined immature AML subgroup with adverse prognosis. AML-M0 leukemias frequently carry loss-of-function RUNX-1 mutation and unsupervised analyses revealed a striking distinction between cases with and without mutations. RUNX1 mutant AML-M0 samples showed a distinct up-regulation of B-cell-related genes, e.g. members of the B-cell receptor complex, transcriptions regulators RUNX3, ETS2, IRF8 or PRDM1 and major histocompatibility complex class II genes. Importantly, expression of one single gene, i.e. BLNK, enabled prediction of RUNX1 mutations in AML-M0 with high accuracy. We propose that RUNX1 mutations in this subgroup of AML cause lineage infidelity, leading to aberrant co-expression of myeloid and B-lymphoid genes in the same cells.
Gene expression profiling of minimally differentiated acute myeloid leukemia: M0 is a distinct entity subdivided by RUNX1 mutation status.
Specimen part
View SamplesBackground
Loss of photoreceptorness and gain of genomic alterations in retinoblastoma reveal tumor progression.
Specimen part
View SamplesIn order to identify the gene targets of frequently altered chromosomal regions in retinoblastoma, a meta-analysis of genome-wide copy number alterations studies on primary retinoblastoma tissue and retinoblastoma cell lines was performed. Published studies were complemented by copy number and gene expression analysis on primary and cell line samples of retinoblastoma. This dataset includes the gene expression data of the retinoblastoma cell lines
A Meta-Analysis of Retinoblastoma Copy Numbers Refines the List of Possible Driver Genes Involved in Tumor Progression.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Histone methyltransferase MLL3 contributes to genome-scale circadian transcription.
Specimen part, Time
View SamplesTotal RNA was isolated from liver samples of C57/BL6 mice over a circadian time course, 3 biological replicate samples per time point were collected and processed individually. RNA from each individual biological replicate sample was extracted using RNeasy mini kit (Qiagen Cat# 74106) and hybridized on an Affymetrix mouse Gene ST1.0 microarray.
Histone methyltransferase MLL3 contributes to genome-scale circadian transcription.
Specimen part, Time
View SamplesA previously predictive CEBPA double mutant (CEBPAdm) signature was hampered by the recently reported CEBPA silenced AML cases that carry a similar gene expression profile (GEP). Two independent AML cohorts were used to train and evaluate the predictive value of the CEBPAdm signature in terms of sensitivity and specificity. A predictive signature was created, containing 25-probe sets by using a logistic regression model with Lasso regularization, which selects discriminative probe sets between the classes, CEBPAdm and all other AML cases, CEBPA wild type (CEBPAwt) and CEBPA single mutant (CEBPAsm). Subsequently, a classifier was trained on the entire HOVON-SAKK cohort based on a two-class approach; CEBPAdm versus all other cases (CEBPAwt and CEBPAsm). This trained classifier subsequently classified 16 candidate CEBPAdm cases in the AMLSG-cohort out of 154 AML cases. This approach showed perfect sensitivity and specificity (both 100%). In addition, we have performed a classification between CEBPAdm ,CEBPAsm, and CEBPAwt to infer if we were able to accurately classify CEBPAsm cases. We observed that all CEBPAsm cases were classified as CEBPAwt, thus CEBPAsm cases do not have a consistent gene expression pattern and are different from the CEBPAdm group.
Prognostic impact, concurrent genetic mutations, and gene expression features of AML with CEBPA mutations in a cohort of 1182 cytogenetically normal AML patients: further evidence for CEBPA double mutant AML as a distinctive disease entity.
No sample metadata fields
View SamplesmRNA profiles of thousands of human tumors are available, but methods to deduce oncogenic signaling networks from these data lag behind. It is especially challenging to identify main-regulatory routes, and to generalize conclusions obtained from experimental models. We designed the bioinformatic platform R2 in parallel with a wet-lab approach of neuroblastoma. Here we demonstrate how R2 facilitates an integrated analysis of our neuroblastoma data. Analysis of the MYCN pathway suggested important regulatory connections to the polyamine synthesis route, the Notch pathway and the BMP/TGF pathway. A network of genes emerged connecting major oncogenes in neuroblastoma. Genes in the network carried strong prognostic values and were essential for tumor cell survival.
Sequencing of neuroblastoma identifies chromothripsis and defects in neuritogenesis genes.
Specimen part
View SamplesAlmost a quarter of pediatric patients with Acute Lymphoblastic Leukemia (ALL) suffer from relapses. The biological mechanisms underlying therapy response and development of relapses have remained unclear. In an attempt to better understand this phenomenon, we have analyzed 41 matched diagnosis relapse pairs of ALL patients using genomewide expression arrays (82 arrays) on purified leukemic cells. In roughly half of the patients very few differences between diagnosis and relapse samples were found (stable group), suggesting that mostly extra-leukemic factors (e.g., drug distribution, drug metabolism, compliance) contributed to the relapse. Therefore, we focused our further analysis on 20 samples with clear differences in gene expression (skewed group), reasoning that these would allow us to better study the biological mechanisms underlying relapsed ALL. After finding the differences between diagnosis and relapse pairs in this group, we identified four major gene clusters corresponding to several pathways associated with changes in cell cycle, DNA replication, recombination and repair, as well as B cell developmental genes. We also identified cancer genes commonly associated with colon carcinomas and ubiquitination to be upregulated in relapsed ALL. Thus, about half of relapses are due to selection or emergence of a clone with deregulated expression of a genes involved in pathways that regulate B cell signaling, development, cell cycle, cellular division and replication.
Genome-wide expression analysis of paired diagnosis-relapse samples in ALL indicates involvement of pathways related to DNA replication, cell cycle and DNA repair, independent of immune phenotype.
Sex, Specimen part, Disease
View SamplesBackground and Purpose—Analyzing genes involved in development and rupture of intracranial aneurysms can enhance knowledge about the pathogenesis of aneurysms, and identify new treatment strategies. We compared gene expression between ruptured and unruptured aneurysms and control intracranial arteries. Methods—We determined expression levels with RNA sequencing. Applying a multivariate negative binomial model, we identified genes that were differentially expressed between 44 aneurysms and 16 control arteries, and between 22 ruptured and 21 unruptured aneurysms. The differential expression of 8 relevant and highly significant genes was validated using digital polymerase chain reaction. Pathway analysis was used to identify enriched pathways. We also analyzed genes with an extreme pattern of differential expression: only expressed in 1 condition without any expression in the other. Results—We found 229 differentially expressed genes in aneurysms versus controls and 1489 in ruptured versus unruptured aneurysms. The differential expression of all 8 genes selected for digital polymerase chain reaction validation was confirmed. Extracellular matrix pathways were enriched in aneurysms versus controls, whereas pathways involved in immune response and the lysosome pathway were enriched in ruptured versus unruptured aneurysms. Immunoglobulin genes were expressed in aneurysms, but showed no expression in controls. Conclusions—For rupture of intracranial aneurysms, we identified the lysosome pathway as a new pathway and found further evidence for the role of the immune response. Our results also point toward a role for immunoglobulins in the pathogenesis of aneurysms. Immune-modifying drugs are, therefore, interesting candidate treatment strategies in the prevention of aneurysm development and rupture. Overall design: RNA sequencing of 44 intracranial aneurysm samples (including 21 unruptured, 22 ruptured and 1 undetermined) and 16 control samples of the intracranial cortical artery
RNA Sequencing Analysis of Intracranial Aneurysm Walls Reveals Involvement of Lysosomes and Immunoglobulins in Rupture.
Sex, Age, Subject
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