IFNG and laryngotracheoesophageal cleft: As the disease progresses from LC to HCC, the frequency of circulating PD-1 (+) CD8+ T cells increases. Tumor-infiltrating CD8+ T cells showed a dramatic increase in PD-1 expression. In vitro, CD8+ T cells induced PD-L1 expression on HCC cells in an IFN-γ dependent manner, thereby promoting APOPTOSIS of CD8+ T cells, while blocking PD-L1 reversed this effect.