Activation of transcription factors induces NK cells expressing and secreting various cytokines, including FasL, tumor necrosis factor (TNF), and TNF-related apoptosis-inducing ligand, which kills tumor cells via the Fas/FasL pathway and the TNFα/TNF-receptor 1 (TNF-R1) pathway (Fig. 1). This evidence concerns the gene TNF and neoplasm.