The Cancer Genome Atlas expression profiles of low-grade gliomas

Abstract

<jats:p>Differentiating between low-grade gliomas (LGGs) of astrocytic and oligodendroglial origin remains a major challenge in neurooncology. Here the authors analyzed The Cancer Genome Atlas (TCGA) profiles of LGGs with the goal of identifying distinct molecular characteristics that would afford accurate and reliable discrimination of astrocytic and oligodendroglial tumors. They found that 1) oligodendrogliomas are more likely to exhibit the glioma-CpG island methylator phenotype (G-CIMP), relative to low-grade astrocytomas; 2) relative to oligodendrogliomas, low-grade astrocytomas exhibit a higher expression of genes related to mitosis, replication, and inflammation; and 3) low-grade astrocytic tumors harbor microRNA profiles similar to those previously described for glioblastoma tumors. Orthogonal intersection of these molecular characteristics with existing molecular markers, such as IDH1 mutation, TP53 mutation, and 1p19q status, should facilitate accurate and reliable pathological diagnosis of LGGs.</jats:p>

Down-regulation of MicroRNA-126 in Glioblastoma and its Correlation with Patient Prognosis: A Pilot Study

“…cancer stem cell versus regular cancer cells; see below for more details). A study comparing the expression of miR-126 in oligodendroglioma and astrocytoma (24 patients: two WHO grade II and 22 WHO grade III) found that astrocytomas expressed less miR-126 than oligodendrogliomas (fold change=0.479) (23). Lately, miR-126, miR-137 and miR-128 were found to be most overexpressed in non-differentiated glioblastoma spheroid cultures containing stem cell-like tumor .…”

Differential mRNA and miRNA expression in oligodendrogliomas of different grades of malignancy

“…Importantly, the LLGs patients with IDH mutations and 1p/19q co-deletions had the most favourable clinical outcomes. Moreover, their gliomas harboured mutations in CIC, FUBP1, NOTCH1, and the TERT promoter [7], which are very consistent with as proposed by Gonda et al, [22].…”

“…A cluster-of-cluster analysis of mRNA, copy number, microRNA (miRNA) and methylation analyses reinforced the clear separation of three molecular classes of LGG based on the status of IDH1/2 and 1p/19q [22]. These data illustrate a potential stratification of LGGs that emphasizes molecular characteristics.…”

“…These data illustrate a potential stratification of LGGs that emphasizes molecular characteristics. IDH wt LGG have molecular alterations and clinical behaviour similar to GBMs, whereas IDH mutant LGGs segregate based on 1p/19q status [22].…”

“…TCGA based analysis of such molecular features suggests that incorporation of these molecular platforms and orthogonal intersection of molecular characteristics with existing genetic markers, such as IDH1 mutation, TP53 mutation, and 1p19q status, should facilitate accurate and reliable pathological diagnosis of diffuse gliomas [7,22]. Moreover, the retrospective analysis of sequencing results by next-generation platforms may improve the diagnosis/classification in gliomas [23].…”