Previously, we demonstrated in the oligodendroglioma PDCs that TERT expression is reduced upon GABPB1 inhibition.42 These recurrent astrocytoma and oligodendroglioma PDCs are therefore suitable for studying mechanisms underlying tumor cell immortality, including ALT and telomerase activation driven by TERTp-mutation.43,44. Here, TERT is linked to astrocytoma (excluding glioblastoma).