The aim of the present study was therefore to compare the precision of fluorescent in situ hybridization (FISH), immunohistochemistry (IHC) for nuclear RelA accumulation and DNA methylation‐based classification, besides conventional histopathology in the diagnostics of RELA ependymomas in a retrospective series of 40 pediatric brain tumors diagnosed as supratentorial ependymomas by histopathological assessment in the past. This evidence concerns the gene RELA and ependymoma.