FOXO1 and pilocytic astrocytoma: As previously described, gene fusions that are rare in adult tumors appear recurrently in pediatric tumors such as BRAF/KIAA1549 in pilocytic astrocytoma (PA) [15], C11orf95/RELA [16] in supratentorial ependymoma (EPN), PAX3/FOXO1 and PAX7/FOXO1 in alveolar RMS [17], and variants involving the EWS gene (EWS/FLI1, EWS/ERG and others less frequent) in EWS [18]; the majority of these fusions involve transcription factors associated with the development/differentiation of the affected tissue.