PDCD1 and hepatocellular carcinoma: Consistent with the associations found in this study, PD1 +8669 genotypes GG and AG, which were related to longer OS of the HBV-related HCC patients, were associated with lower PD-1 mRNA levels [12] and the downregulation of PD-1 expression and upregulation of tumor necrosis factor (TNF)-α and interferon (IFN)-γ in patients with chronic HBV infection through interaction with miR-4717 [19].