Abscopal effects have been shown to be mediated, in part, by PD-1 as administration of a single fraction of 15 Gy by stereotactic ablative radiotherapy (SABR) to the primary tumor in a melanoma subcutaneous mouse model resulted in significant reduction in tumor volumes of secondary nonirradiated tumors in PD-1-knockout mice compared to PD-1-wild-type (WT) mice [87]. Here, PDCD1 is linked to melanoma.