AKR1D1 and hepatocellular carcinoma: Following over-expression of AKR1D1 in HepG2 and HEK293 cells, cortisone clearance and 5β-THE generation were increased, providing additional evidence for the potent ability of AKR1D1 to regulate steroid hormone availability within human hepatoma cells (Supplementary Figs. 2d–g and 3a–d).