Tumor cell killing is achieved by multiple mechanisms: degranulation, i.e., the release of the cytolytic granules containing perforin and granzyme; antibody-dependent cellular cytotoxicity (ADCC), ignited by the CD16 receptor-mediated identification of antibody-coated target cells; and the induction of tumor cell apoptosis by expressing tumor necrosis factor α (TNF-α), FasL, or TNF-related apoptosis-inducing ligands [3,7,8,11,12,13]. Here, PRF1 is linked to neoplasm.