TP53 and astrocytoma (excluding glioblastoma): Sahm et al. performed a reclassification of a series of oligoastrocytoma tumours and found that 1p/19q codeletion and mutation of ARTX and p53 were mutually exclusive, confirming that these tumours with mixed histologic features were ultimately characterized at the molecular level as either oligodendroglioma or astrocytoma.25 They reported that 72% of the cases initially considered oligoastrocytoma had molecular features typical of oligodendroglioma and 25% of astrocytoma, which differs from our study (30% of all oligoastrocytic tumours were characterized as oligodendrogliomas).