PDCD1 and neoplasm: As depicted in Fig. 6a (left graph), administration of anti-PD-1 antibody (nivolumab) to non-hNSG mice had no effect on the tumor size and growth, because tumors in both vehicle- and anti-PD-1-treated animals reached similar volume after days 10–12 of therapy (corresponding to two cycles of i.v. administered anti-PD-1 antibody).