CD274 and neoplasm: Expression of PD-L1 in Myc-CaP cells increases after irradiation (Additional file 1: Figure S1). Compared to mice treated with antibody alone, XRT (20 Gy in 2 fractions) to the leg tumor graft causes a local response in the irradiated tumor and a robust abscopal effect with regression of an unirradiated distant tumor graft (Fig. 1a and b).