Molecular and clinical analysis of glioblastoma with an oligodendroglial component (GBMO)

The genetic and clinical features of glioblastoma with an oligodendroglial component (GBMO), pathologically defined as anaplastic oligo-astrocytoma with necrosis, remain unclear. We investigated the correlation between genetic alterations and clinical outcomes in 19 GBMO patients we have encountered since 1997. Using single nucleotide polymorphism oligonucleotide genomic (SNP) microarrays, we analyzed gene amplification, loss of heterozygosity (LOH), and homozygous deletions in their whole genome. We also analyzed their overall survival (OS). Pathological studies revealed the presence of calcification in 11 and of a cyst in 9 of the 19 patients. Whole-genome analysis using SNP microarrays revealed LOH of chromosome 10 in 11, EGFR amplification in 8, 9p21 (INK4 locus) deletion in 12, PDGFR amplification in 2, and LOH of 1p19q in 2 patients. Median OS was 14 months (average 22.8 months). The pattern of genetic alterations was similar in GBMO and glioblastoma multiforme (GBM) patients, and the clinical outcomes were similar in GBMO and GBM patients.