In particular, as radiotherapy is known to induce immunogenic cell death by releasing tumour-associated antigens and danger signals (DAMPs) which, in turn, cause cytokine release (including Interferon gamma, a positive regulator of PD-L1), the recruitment of dendritic cells, and the proliferation of CD8+ T cells, we would normally expect an increased expression of this biomarker after irradiation [26,62]. This evidence concerns the gene CD274 and neoplasm.