The underlying molecular mechanism could be the release of tumor antigen, triggered by radiotherapy-induced immunogenic cell death, and a subsequent systemic anti-tumor immune response, mediated by the checkpoint-inhibitor which reactivates the immune system by blocking the inhibitory signals on the immune cells (e.g. programmed cell death protein 1) (Formenti & Demaria, 2009). The gene discussed is PDCD1; the disease is neoplasm.