SiRNA targeted at STAT3 mRNA induces increased apoptosis in many types of cancer cells via down-regulation of antiapoptotic proteins, including Bcl-2 and Bcl-XL [158,159,160] and up-regulation of pro-apoptotic proteins, such as Fas, Fas-L, caspase-3 and Bax [159,161], via recruiting FADD, which forms complex with caspase 8, Fas, and Fas-L to activate apoptotic pathways, sequential caspase activation to induce mitochondrial dysfunction, and Bax translocation. The gene discussed is FAS; the disease is cancer.