However, reports on the impact of pan-HDACis on previously activated effector T cells show that when applied after the initial activation of CD4 T cells, the pan-HDACi trichostatin A prevents FasL-driven activation-induced cell death, increases infiltration of CD4 T cells into the tumor, and reduces tumor growth in lymphoma and melanoma murine models [137,217]. This evidence concerns the gene CD4 and neoplasm.