Immune effector elements, including T cells, NK cells, monocyte/macrophages, and antibodies can directly kill tumors through lytic/cytostatic mechanisms by secreting perforin/granzymes, or inducing tumor cytostatis or apoptosis; or indirectly mediate tumor inhibition via attacking tumor supportive elements such as endothelial or stromal cells. The gene discussed is PRF1; the disease is neoplasm.