To evaluate the potential immunogenic modulation of high doses RT and the consequent “vaccine-like” effect of local irradiation, we monitored the presence and the amount of circulating CD4+ and CD8+ T cell responses against known epitopes derived from the BC-associated antigens survivin, mammaglobin-A, and HER2/neu before and after RT, globally in 16 patients (due to availability of biological material collected 1 month after RT) enrolled in this study (exemplary flow cytometry dot plots are shown in Figure S1 in Supplementary Material). This evidence concerns the gene CD8A and breast cancer.