TLR activation provokes the infiltration of natural killer (NK) cells, cytotoxic T cells and type I T helper cells into the tumor, where they induce tumor cell lysis via secretion of e.g., perforin and IFN-γ (interferon gamma) which results in the release of type I IFNs (IFN-α, β) [39,40,41]. Here, PRF1 is linked to neoplasm.