PDCD1 and hepatocellular carcinoma: CD8+ T cells have shown higher expression of inhibitory molecules (CTLA-4, PD-1 and TIM-3) in HBV and HBV-HCC and high expression of programmed cell death protein 1 (PD-1) on HBV-specific T and B cells has led to exhaustion of T cells and decreased production of antibodies (184–186).