FN1 and glioblastoma: We demonstrate that, in the highly proliferative and less diffuse GL261 tumor model that resembles the core of glioblastoma, PpIX and FNa fluorescence are associated with similarly high TP rates, and both can miss some of the tumor (presence of FN areas), but FNa is associated with a higher FP rate for staining surrounding edematous tissue, choroid plexus, and dura.