More recently, with the appearance of mass genome sequencing techniques, inactivating mutations were identified in the alpha thalassemia/mental retardation syndrome X-linked (ATRX), death-domain associated protein (DAXX) and Histone 3.3 complex in ALT-positive tumor cells, mainly in pancreatic endocrine tumors [13], glioblastoma multiforme, oligodendrogliomas [14] and others. Here, GPT is linked to pancreatic neuroendocrine tumor.