It has been highlighted that inactivating mutations in the ATRX/DAXX/H.3.3 complex in cells displaying alternative lengthening of telomeres (ALT) phenotype, including pancreatic neuroendocrine tumors [9], glioblastoma multiform, oligodendrogliomas, medulloblastomas [10] and neuroblastomas [11], support the potential role of ATRX as a tumor suppressor. The gene discussed is ATRX; the disease is glioblastoma.