Expression data from different grades (WHO) of astrocytomas (ACM)

The aim of the study was to identify significant alterations in genes and molecular functional pathways in comparison with normal and ACM tissue, and detect the marker genes to differentiate the different stage astrocytomas Total RNA was isolated from Seventeen tumor tissue of patients, which included two WHO grade I(T1) and five WHO grade II(T2), III(T3) and IV(T4) samples, and four pooled normal tissue samples. The genome-wide expression analysis was first performed by directly comparing the expression profile of highly enriched different grade astrocytomas and pooled normal tissues, we then applied various data-mining methods to process the 15 different grades tumor tissues sample. Paired T-test and Q-cluster method was performed to explore mark genes validated by qRT-PCR. This study utilized a pathway-specific enrichment analysis of the microarray data and quantified the gene expression difference between astrocytomas tumor and pooled normal tissues. BioCarta and KEGG pathways of the ACM compared to normal tissue were identified through enrichment tests on gene lists obtained using SAM, while GO is organized into hierarchical annotations in the context of normal cellular function, the BioCarta and KEGG database organizes the genes(gen products) into pathway reaction maps and functional complexes, including some disease-specific pathway