Table 1.
Molecular diagnostic markers and common genetic alterations in IDH-mutant glioma.
| Category | Alterations | Oligodendroglioma WHO Grade 2 | Oligodendroglioma WHO Grade 3 | Astrocytoma WHO Grade 2/3 | Astrocytoma WHO Grade 4 | |
|---|---|---|---|---|---|---|
| Diagnostic markers | IDH1 or IDH2 mutation | Present | Present | Present | Present | |
| G-CIMP | Present | Present | Present | Present | ||
| ATRX | Inactivated | Inactivated | ||||
| 1p (FUBP1) / 19q (CIC) codeletion | Present | Present | ||||
| TERT | Activated | Activated | ||||
| 9p21 (CDKN2A/B) | Inactivated | |||||
| Necrosis and/or microvascular proliferation | Present | |||||
| Other genomic alterations | TP53 | Inactivated | Inactivated | |||
| Myc | Activated | |||||
| TCF12 | Inactivated | |||||
| 10q (PTEN/MGMT) | Inactivated | |||||
| Signaling pathways | Activation of PI3K signaling through loss of PTEN and gain of mTOR | |||||
| Activation of cell cycle signaling through gain of CDK4, CDK6 and cyclin E2 | ||||||
ATRX, Alpha-thalassemia/mental retardation, X-linked; CDKN2A/B, Cyclin-dependent kinase inhibitor 2A/B; CDK, Cyclin-dependent kinases; CIC, Capicua transcriptional repressor; FUBP1, Far upstream element binding protein 1; G-CIMP, cytosine-phosphate-guanine (CpG) island methylator phenotype; IDH, Isocitrate dehydrogenase; MGMT, Methylguanine-DNA-Methyltransferase; PI3K, Phosphoinositide 3-kinase; PTEN, Phosphatase and tensin homolog; TCF12, Transcription factor 12; TERT, Telomerase reverse transcriptase.