KRT75 and posterior fossa ependymoma: DNA methylation analysis of larger series of posterior fossa ependymomas revealed further heterogeneity within the PFA and PFB groups, identifying two major subgroups (PFA-1 and PFA-2) and nine distinct subtypes (PFA-1a-e and PFA-2a-c) within PFA (Fig. 1) [56], and five distinct PFB subtypes (PFB1-5) [20], all with distinct demographics, copy number alterations and transcriptional profiles.