The percentage of CD8+ cells among the CD3+ T cells on day 25 in IL-2/S-15 group was significant higher than that in IL-2 group which is consistent with our previous data that hyper-IL-15 provides an effective therapy against well-established liver cancers in mouse models by preferentially expanding tumor-specific CD8+ T cells [14, 15]. This evidence concerns the gene CD8A and liver cancer.