PDCD1 and neoplasm: Unexpectedly, however, there was little difference in tumor size between mice receiving KS-58 alone and those receiving the combination of KS-58 plus anti-PD-1 (Fig. 2B,D), with tumors exposed to high-dose KS-58 showing a 65% weight reduction compared to controls and tumors exposed to both high-dose KS-58 plus anti-PD-1 showing a 55% reduction (Fig. 2C,D).