CD274 and neoplasm: PD-L1 (programmed death-ligand 1) expression is found to be elevated on tumour cells following irradiation due to interferon gamma (IFN-γ) release from tumour-infiltrating lymphocytes (TILs) (42) and TILs have increased expression of PD-1 (programmed death-1) following ex-vivo irradiation (43).