Overall, current data strongly suggest that the TWEAK/Fn14 effects on LPCs are protective in acute liver damage by promoting liver repair but pathogenetic in chronic liver damage via the induction of liver fibrosis [3, 34, 35], indicating the double-edged roles of TWEAK/Fn14 in liver diseases (Fig. 2). The gene discussed is TNFSF12; the disease is liver disorder.