T and NK cells mediated tumor killing occurs via direct cell cytotoxicity, the release of perforin and granzyme, NK cells antibody-dependent cellular cytotoxicity (ADCC) via engaging their receptor (CD16) or by apoptotic axis intermediated by the Fas ligand (FasL) or the TNF-related apoptosis-inducing ligand (TRAIL). The gene discussed is FCGR3A; the disease is neoplasm.