Th1 cytokines and cytotoxic mediators are essential for T cells to maintain the GVL effect and kill tumor cells, yet they also lead to the damage of healthy host tissues [84,85,86,87], More specifically INF-γ and TNF-α secretion by donor CD4 T cells are the hall mark of persistence of GvHD mediators [88]. This evidence concerns the gene CD4 and neoplasm.