In contrast to the above studies, the numbers of γH2AX and 53BP1 foci (as DSB markers) induced in TrC1 prostate cancer cells and murine embryonic fibroblasts irradiated at the entrance dose of a 187 MeV PBT beam compared to 320 kV photons were observed to be the same 30 min post-irradiation [34]. This evidence concerns the gene TP53BP1 and Familial prostate cancer.