MYCN and ependymoma: The highest frequency of mutations was observed in primary HGG (non-GBM) tumors (4 out of 19 cases, 21.1%), as well as metastatic neuroblastoma MYCN-NA 11qWT, medulloblastoma, and osteosarcoma specimens (4 to 7 cases, 14.3 to 12.7%), whereas no mutation was detected in aRMS, neuroblastoma MYCN-A, carcinoma and LGG tumors, and only two nephroblastoma and ependymoma cases harbored single mutations.