The nearly mutually exclusive mutations of ATRX in astrocytomas and of TERTp in oligodendrogliomas are striking, especially because both genes are key players in TMMs, where the activation of TERT is central in the canonical telomerase-dependent TMM (TEL) [4], while ATRX deactivation seems to be an important factor for inducing the alternative lengthening of telomeres TMM (ALT) [5]. Here, ATRX is linked to oligodendroglioma.