CD8A and hepatocellular carcinoma: While an increased ratio of CD8+ T cells to Tregs had a good prognostic ability, yet surprisingly frequency of CD8+ T cells alone did not predict the outcome (Huang et al., 2012[29]), which indicates that the fine balance between Tregs and CTLs when disrupted leads to HCC progression dominated by an increased frequency of Tregs over CD8+ T cells.