The discovery that Human Epidermal growth factor Receptor 2 (HER2, also name ERBB2), and Receptor tyrosine-protein kinase erbB-4 (ERBB4) are highly expressed in the most aggressive forms of medulloblastoma [124] and ependymomas [125], while Epidermal Growth Factor Receptor (EGFR, also name HER1) is amplified and overexpressed in gliomas [126], has strongly driven the development of inhibitors targeting EGFR and ERBB2 receptors. Here, ERBB4 is linked to ependymoma.