ERBB2 and glioblastoma: Increased cell surface density of HER3/ErbB3 is associated with a growing number of metastatic, resistant and brain-localized tumours, including prostate, gastric, colon, lung, pancreatic, head and neck, ovarian, cervical, glioblastoma, melanoma and breast cancers14–17, especially brain-metastatic HER2+ and triple-negative breast tumours18,19.