PDCD1 and neoplasm: SMM103, an anti-PD-1 antibody responsive cell line, was subcutaneously inoculated in immune competent C57BL/6 mice, the mice were randomly divided into two groups when the tumor grew up to ≈80 mm3, and were treated with saline and anti-PD-1 antibody (5mg/kg), respectively (Figure 2A).