PDCD1 and neoplasm: At Day 7 after implantation, tumor-bearing mice were treated by intra-peritoneal injection with CBDCA (100 mg/kg, every 7 days for 2 times), anti-PD-1 antibodies (100 μg/mouse, every second day for 5 times), the combination of both, or saline plus isotype antibodies as controls (CTRL).