IDH1 and oligodendroglioma: Throughout recent years, several authors have proposed the combination of TERTp mutations with other CNS tumour-associated molecular features, namely IDH mutations, 1p19q loss, and O6-methylguanine-DNA-methyltransferase (O6-MGMT) methylation status, willing to establish a molecular signature that could assist more efficiently in defining an accurate prognosis and the best therapeutic option in patients with diffuse astrocytic and oligodendroglial tumours.