FOS and glioblastoma: To investigate if NMDAR-induced DSBs are also capable of regulating the transcription of genes in GBM cells, we chose to analyze the impact of NMDAR signaling and Top2β activity on the expression of the early response gene (ERG) cFos, a protein which is expressed upon the Top2β-mediated DSB-induction in neurons [9] and has been implicated in GBM malignancy [35].