Glioblastoma
Features of primary and secondary GBM
| Feature | Primary glioblastoma | Secondary glioblastoma |
|---|---|---|
| Molecular signature | IDH-wildtype (in 95%) | IDH-mutant (in 60–90%) |
| Precursor lesion | None identified, diffuse astrocytoma, arise de novo | Anaplastic astrocytoma |
| Proportion of GBMs | ≈ 90% | ≈ 10% |
| Median age at diagnosis | ≈ 62 years | ≈ 44 years |
| Male:Female ratio | 1.42:1 | 1.05:1 |
| Mean length of clinical history | 4 months | 15 months |
| Median overall survival (surgery + XRT) | 9.9 months | 24 months |
| Median overall survival (surgery + XRT + chemo) | 15 months | 31 months |
| Location | Temporal > Parietal > Frontal lobe predilection | Occipital > Temporal |
| Necrosis | Extensive | Limited |
| TERT promoter mutations | 72% | 26% |
| TP53 mutations | 27% | 81% |
| ATRX mutations | Exceptional | 71% |
| EGFR amplification | 35% | Exceptional |
| PTEN mutations | 24% | Exceptional |
| MGMT promoter gene methylation | 36% | 75% |