ERVFRD-1 and glioblastoma: Our here described findings add to a report of cytotoxic stress within chemo-resistant glioblastoma cells mediated by related HERV-WE1 (syncytin-1) and HERV-FRD1 (syncytin-2) proteins and shown to trigger large-scale fission of mitochondria (Diaz-Carballo et al., 2017).