ATRX and pediatric osteosarcoma: On the contrary, de novo null mutations in the ATRX gene have been detected in at least 15 different types of cancers including neuroblastoma, glioma, pancreatic neuroendocrine tumors (panNETs), and pediatric osteosarcoma [6,7,8,9,10,11,12,13] and recently ATRX gene status has become a critical marker that defines molecular World Health Organization (WHO) classification of tumors of the central nervous system, such as glioma [14].