123]. Furthermore, overexpression of HER2, EGFR4, and the EGFR4 ligand NRG1-beta in medulloblastoma results in increased metastasis [124]. Likewise over-expression of EGFR4 in conjunction with EGFR1 and HER2 results in breast cancers correlates with poor prognosis [125]. Here, ERBB2 is linked to breast cancer.