DO_cancer_slim NCIthesaurus posterior fossa ependymoma posterior fossa group B ependymoma DOID:0081255 disease_ontology ICDO:9396/3 A posterior fossa ependymoma that arises in the posterior fossa with characteristic DNA methylation patterns including retention of nuclear H3 p.K28me3 (K27me3) expression, absence of CpG island hypermethylation, absence of global DNA hypomethylation, and absence of EZHIP overexpression. NCI:C186451 Posterior Fossa Ependymoma, Group B (PFB) Posterior fossa group B (PFB) ependymoma