Here, we review the recent literature on molecular discoveries in ependymomas 
and pediatric diffuse gliomas. Ependymomas can now be categorized into three 
location-related subgroups according to their biological profile: posterior 
fossa ependymomas, group A (PFA) and B (PFB), and supratentorial ependymomas. 
Although no recurrently mutated genes were found throughout these groups of 
ependymomas, PFA exhibited a CpG island methylator phenotype, PFB was associated 
with extensive chromosomal aberrations, and the C11orf95-RELA fusion gene was 
frequently observed in supratentorial ependymomas. Meanwhile, it has now become 
apparent that pediatric diffuse gliomas have a distinct genetic status from 
their adult counterparts, even though they share an indistinguishable histology. 
In pediatric low-grade diffuse gliomas, an intragenic duplication of the portion 
of FGFR1 encoding the tyrosine kinase domain (TKD) and rearrangements of 
MYB/MYBL1 were found recurrently and mutually exclusively. As for non-brainstem 
high-grade tumors, in addition to H3F3A, TP53, and ATRX mutations, which were 
frequently observed in older children, recurrent fusions involving NTRK1, NTRK2, 
and NTRK3 were reported in infants younger than 3 years of age. Moreover, in 
diffuse intrinsic pontine gliomas (DIPG), recurrent somatic mutations of ACVR1 
were found in association with HIST1H3B mutations.