PRF1 and neoplasm: The plausible explanations indicates towards following distinctives of Tregs cells in regulating the tumour microenvironment, including apoptosis induction of effector cells through the CD25+ mediated diminution of IL-2; cytolysis of effector T cells mediated by granzyme B and perforin; dendritic cells maturation and functioning regulated through CTLA-4 mediated cell-cell contact-dependent mechanism; and alteration in the effector cell immune response through the liberation of inhibitory cytokines such as TGF-β and IL-10 [94,95].