In contrast, Lohse et al. [11], also using FFF X-ray beams from a Varian TrueBeam Linac, reported reduced clonogenic cell survival for two commercial GBM lines, namely the T98G (p53 mut) and U87-MG (p53-wt), irradiated with increasing dose rates (between 0.2 Gy/min and 24 Gy/min). This evidence concerns the gene TP53 and glioblastoma.