These results illustrate that FACS and NanoString analysis of TRAMP-C1 tumours following 3 × 5 Gy suggests a DC immune response at 7-days post-treatment, along with increased PD-1 expression in CD45+CD8+ T-cells at the tumour regrowth end-point, which may be harnessed by iRT targeting PD1/PD-L1. Here, CD8A is linked to neoplasm.