While GANT61 increased the cell-intrinsic radiosensitivity of PCa cells in vitro in a p53-dependent manner through the induction of G1-arrest and apoptosis, the enhanced effect of radiotherapy due to GANT61 treatment in vivo seems to be independent of tumoral p53-status since radiosensitization was observed both in a PC3 and 22Rv1 xenograft model. Here, TP53 is linked to posterior cortical atrophy.