In correlation with the low numbers of CD8+ T-cells observed in the tumor stroma, evidence of the immunosuppressive character of the M5-T1 tumor was provided by the downregulation of two proteins, a member of the RT1 class I histocompatibility complex of the rat [53], a crucial element for the induction of CD8+ T-cell adaptive immune responses against tumors [54], and GIMA4, which belongs to the immunity-associated protein family involved in T-lymphocyte biology [55], two members of this family being downregulated in hepatocellular carcinoma compared with normal tissues [56]. This evidence concerns the gene CD8A and neoplasm.