TNF and melanoma: Primed and activated CD8+ cytotoxic T lymphocytes (Tc) act on melanoma cells directly, by releasing perforin and granzyme B, which induce apoptosis, or indirectly, through the secretion of cytokines, including interferon-γ (IFN-γ) and tumor necrosis factor (TNF), which leads to the consecutive appearance of antigens and the expansion of T cells [10,12,13,14].