TWEAK/Fn14 signaling can have anti-tumorigenic effects (reviewed in [4], [22]); for example, TWEAK is a pro-apoptotic factor for some human cancer cell lines, and two companies have developed agonistic Fn14 antibodies that can kill cancer cells in vitro and inhibit xenograft tumor growth in vivo[23], [26]–[28]. The gene discussed is TNFSF12; the disease is cancer.