PDCD1 and hepatocellular carcinoma: Emerging evidence indicates that PD-1 signaling in DCs may inhibit survival41 and decrease secretion of IL-12 and TNF-α, suppressing the antitumor potential of CD8+ T cells.42 PD-1 signaling in DCs also engages the canonical NF-κB pathway and suppresses antigen presentation machinery by blocking surface expression of MHCI.40 43 In vivo models of hepatocellular carcinoma support an immunosuppressive role for PD-1 in DCs.