Table 1.

Clinical and genetic features of glioblastomas with and without IDH1 mutations

Glioblastomas with IDH1 mutationGlioblastomas without IDH1 mutationP
No. of cases36 cases (8.8%)371 cases (91.2%)
Age at GBM diagnosis47.9 ± 12.9 y60.6 ± 13.5 y<0.0001
Male/female ratio1.121.46N.s.
Clinical history*15.2 ± 45.8 mo3.9 ± 10.8 mo0.0003
Primary/secondary GBM14/22 (0.64)363/8 (45.4)<0.0001
Median overall survival24.0 mo (n = 17)9.9 mo (n = 186)<0.0001
Mean overall survival27.1 ± 18.0 mo (n = 17)11.3 ± 7.1 mo (n = 186)<0.0001
Hazard ratio (95% CI)§0.288 (0.163-0.508)1<0.0001
Genetic alterations
    TP53 mutation26/32 (81.3%)88/331 (26.6%)<0.0001
    EGFR amplification2/31 (6.5%)115/329 (35.0%)0.0005
    p16INK4a deletion5/23 (21.7%)86/284 (30.3%)N.s.
    PTEN mutation2/25 (8.0%)66/274 (24.1%)N.s.
    LOH 1p5/21 (23.8%)34/227 (15.0%)N.s.
    LOH 10q16/22 (72.7%)145/220 (66.6%)N.s.
    LOH 19q6/19 (31.6%)9/230 (3.9%)<0.0001

Abbreviations: GBM, glioblastoma; N.s., not significant; CI, confidence interval; y, years; mo, months.

  • *Time from the first clinical symptom to glioblastoma diagnosis.

  • Tumors were considered primary when a glioblastoma diagnosis was made at the first biopsy, without clinical or histologic evidence of a preexisting, less malignant precursor lesion. A diagnosis of secondary glioblastoma was made only in cases with clinical and histologic evidence of a preceding low-grade or anaplastic glioma.

  • Following surgery and radiotherapy.

  • §Adjusted for age and gender.