IDH1 Mutations as Molecular Signature and Predictive Factor of Secondary Glioblastomas

PURPOSE: To establish the frequency of IDH1 mutations in glioblastomas at a population level, and to assess whether they allow reliable discrimination between primary (de novo) glioblastomas and secondary glioblastomas that progressed from low-grade or anaplastic astrocytoma. EXPERIMENTAL DESIGN: We screened glioblastomas from a population-based study for IDH1 mutations and correlated them with clinical data and other genetic alterations. RESULTS: IDH1 mutations were detected in 36 of 407 glioblastomas (8.8%). Glioblastoma patients with IDH1 mutations were younger (mean, 47.9 years) than those with EGFR amplification (60.9 years) and were associated with significantly longer survival (mean, 27.1 versus 11.3…