HMOX1 and renal fibrosis: HO-1 [9, 10], Notch [8, 11], EGFR [12], transforming growth factor-β1 (TGF-β) [7, 13], Wnt [5, 8], and Hedgehog [14] signaling have come into focus as not only key regulatory molecules but also targets for treatment of EMT and renal fibrosis.