GFAP and central nervous system cancer: The HSV-TK/GCV system has been previously used to ablate rat glioma cells (C6 cell line), murine cerebellar neural stem cells (C17.2 cell line), murine GFAP-expressing definitive neural stem cells, and human-ESC-derived, Ki67+ NPCs (Imura et al., 2003; Morshead et al., 2003; Li et al., 2005; Pu et al., 2011; Sachewsky et al., 2014; Tieng et al., 2016).