Gliomas were assigned to one of the three molecular groups: Group O (IDH-mutant, 1p/19q co-deleted oligodendrogliomas, n = 95), Group A (IDH-mutant, ATRX inactivated astrocytomas, n = 175) and Group G (IDH wild-type, GBM-like, n = 46).
Oligodendrogliomas with a mutant IDH1 had noteworthy enhanced expression of enzymes controlling aerobic glycolysis and detoxification, and anti-apoptosis proteins.
Distinct spectral profiles were observed for lesions with IDH-mutated genotypes, between astrocytoma and oligodendroglioma histologies, as well as for tumors that had undergone MP.
A total of 135 cases consisted of 38 IDH-mutant [17 astrocytoma (AC), 13 oligodendroglioma (OD) and eight glioblastoma (GBM)], 87 IDH-wildtype (six AC, three OD and 78 GBM), and 10 diffuse midline glioma, H3K27M-mutant.
We found 165 IDH1 (72.7%) and 2 IDH2 mutations (0.9%) in 227 diffuse astrocytomas WHO grade II, 146 IDH1 (64.0%) and 2 IDH2 mutations (0.9%) in 228 anaplastic astrocytomas WHO grade III, 105 IDH1 (82.0%) and 6 IDH2 mutations (4.7%) in 128 oligodendrogliomas WHO grade II, 121 IDH1 (69.5%) and 9 IDH2 mutations (5.2%) in 174 anaplastic oligodendrogliomas WHO grade III, 62 IDH1 (81.6%) and 1 IDH2 mutations (1.3%) in 76 oligoastrocytomas WHO grade II and 117 IDH1 (66.1%) and 11 IDH2 mutations (6.2%) in 177 anaplastic oligoastrocytomas WHO grade III.
Several studies on molecular profiling of oligodendrogliomas (OGs) in adults have shown a distinctive genetic pattern characterized by combined deletions of chromosome arms 1p and 19q, O6-methylguanine-methyltransferase (MGMT) methylation, and isocitrate dehydrogenase 1 (IDH1) mutation, which have potential diagnostic, prognostic, and even therapeutic relevance.
Next-generation molecular biology technologies have recently identified recurrent CIC and FUBP1 point mutations in 1p/19q codeleted and IDH-mutated oligodendrogliomas.
One hundred twenty-six tumors could be classified: 20 as type II (IDH mutation [mut], "astrocytoma"), 49 as type I (1p/19q codeletion, "oligodendroglioma"), 55 as type III (7+/10q- or TERTmut and 1p/19q intact, "glioblastoma"), and 2 as childhood glioblastoma (H3F3Amut), leaving 7 unclassified (total 91% classified).
A total of 221 somatic IDH1 mutations were detected and the highest frequencies occurred in diffuse astrocytomas (68%), oligodendrogliomas (69%), oligoastrocytomas (78%) and secondary glioblastomas (88%).
The first of these enzymes is isocitrate dehydrogenase 1 (IDH1), which is mutated in secondary glioblastomas and ~70% of grade II/III astrocytomas and oligodendrogliomas.
We excluded glioblastoma-like tumors (7a10d subgroup) and derived a gene expression signature distinguishing histologically classified oligodendrogliomas with concurrent 1p/19q co-deletion and IDH mutation (1p/19q subgroup) from those with predominant IDH mutation alone (IDHme subgroup).
Mutations of the isocitrate dehydrogenase (IDH) metabolic enzymes IDH1 and IDH2 have been found to be frequent and early genetic alterations in astrocytomas and oligodendrogliomas.
Here we profile 4,347 single cells from six IDH1 or IDH2 mutant human oligodendrogliomas by RNA sequencing (RNA-seq) and reconstruct their developmental programs from genome-wide expression signatures.
The DSC-MRI procedure may provide insight into the IDH1/2 mutation and ATRX expression status and MGMT methylation profile of diffuse glioma; however, taking integrated oligodendroglioma into account limits the diagnostic performance of rCBV in non-invasively predicting the molecular subtype.
Furthermore, identification of a common IDH1 mutation in enchondroma and oligodendroglioma-matched pair specimens supports the hypothesis that IDH1/2 mosaicism initiates tumorigenesis.
To investigate the relationship between 3 hypoxic markers, carbonic anhydrase-9 (CA-9), hypoxia-inducible factor (HIF)-1α, and HIF-2α and the traditional genetic markers, deletions of chromosomes 1p and 19q and Isocitrate dehydrogenase 1 (IDH1) R132H mutation in oligodendrogliomas.
Mutations in the isocitrate dehydrogenase (IDH) genes occur frequently in low-grade astrocytomas and oligodendrogliomas (World Health Organization [WHO] grade II), and in higher-grade gliomas (WHO grades III and IV) that arise after malignant progression of low-grade tumors.
The relationship between chromosome 1p and 19q deletions and treatment responsive oligodendrogliomas is discussed, as are the newer advances relating to silencing of the MGMT gene in astrocytomas and mutations in the IDH-1 gene in both astrocytomas and oligodendrogliomas.