In mice bearing H22 hepatoma cell-derived tumors, intraperitoneal administration of cinobufagin can stimulate the proliferation of CD3+, CD4+, and CD8+ T cells, which in turn increases the expression of the β-END, POMC, and μ-OR proteins in xenograft tissues and blocks peripheral μ-ORs to elicit an analgesic effect. This evidence concerns the gene CD8A and hepatocellular carcinoma.