Related Experiment Videos
Expression analysis of juvenile pilocytic astrocytomas by oligonucleotide microarray reveals two potential subgroups
Kwong-Kwok Wong1, Yi-Mieng Chang, Yvonne T M Tsang
1Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA. kkwong@bcm.tmc.edu
Cancer Research
|January 25, 2005
Summary
Juvenile pilocytic astrocytoma (JPA), a common pediatric brain tumor, shows deregulated gene expression. Two distinct JPA subgroups were identified, with differing gene profiles linked to tumor progression.
Area of Science:
- Neuro-oncology
- Pediatric oncology
- Molecular biology
Background:
- Juvenile pilocytic astrocytoma (JPA) is a prevalent pediatric brain tumor.
- Understanding gene expression in JPA is crucial for identifying potential therapeutic targets and prognostic markers.
Purpose of the Study:
- To analyze gene expression profiles in pediatric JPA.
- To identify distinct molecular subgroups within JPA.
- To correlate gene expression patterns with tumor characteristics and potential progression.
Main Methods:
- Gene expression profiling of 21 JPAs using Affymetrix GeneChip U133A.
- Comparison with normal cerebellar samples.
- Unsupervised hierarchical clustering of 848 highly covariant genes to identify subgroups.
- Supervised analysis using Significance Analysis of Microarrays (SAM) to find differentially expressed genes.
- Immunostaining for myelin basic protein (MBP) in 18 incompletely resected JPAs.
Main Results:
- Significant deregulation of genes involved in neurogenesis, cell adhesion, synaptic transmission, CNS development, potassium ion transport, protein dephosphorylation, and cell differentiation was observed in JPA.
- Two major JPA subgroups were identified through hierarchical clustering.
- Supervised analysis revealed differentially expressed genes related to cell adhesion, cell growth regulation, cell motility, nerve ensheathment, and angiogenesis between the subgroups.
- JPA lacking myelin basic protein-positive cells showed a tendency for progression in incompletely resected tumors.
Conclusions:
- JPA exhibits distinct molecular subtypes with unique gene expression signatures.
- Gene expression patterns, particularly those related to cell adhesion, growth, motility, and angiogenesis, differentiate JPA subgroups.
- Absence of myelin basic protein expression may indicate a higher risk of progression in incompletely resected pediatric pilocytic astrocytomas.