With respect to the recurrences of posterior fossa ependymomas, the upregulation of ribosomal proteins is consistent with increased proliferation usually seen in these tumors at recurrence, depicted for example by increased Ki67 labeling; in medulloblastomas as well, the overexpression of ribosomal proteins has been shown to be the hallmark of aggressive tumors[75]. Here, MKI67 is linked to posterior fossa ependymoma.