STAT3 and renal fibrosis: Numerous studies have shown that multiple signaling pathways (including PI3K/AKT, STAT3 Notch, Wnt/beta-catenin, and Hedgehog) are associated with renal fibrosis fibers (Yang and Liu, 2001; Iwano et al., 2002; Derynck and Zhang, 2003; Lan, 2003; Wang et al., 2005).