PDCD1 and neoplasm: In our preclinical work, programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) were both increased within the tumor by DPX/mCPA treatment, corresponding to increases in cytotoxic genes such as IFN- γ and granzyme B. PD-1 is a co-inhibitory receptor expressed primarily by activated lymphocytes which induces tolerance/exhaustion upon interaction with its ligand PD-L1.