Peer CJ, Sissung TM, Kim A, Jain L, Woo S, Gardner ER, Kirkland CT, Troutman SM, English BC, Richardson ED, Federspiel J, Venzon D, Dahut W, Kohn E, Kummar S, Yarchoan R, Giaccone G, Widemann B, Figg WD. Sorafenib is an inhibitor of UGT1A1 but is metabolized by UGT1A9: implications of genetic variants on pharmacokinetics and hyperbilirubinemia. Clin Cancer Res. 2012 Apr 01; 18(7):2099-107.