AKR1C1 and acute lymphoblastic leukemia: Fig S2A) that were treated with vincristine (VCR), l-asparaginase (ASP), daunorubicin (Dauno), and cytarabine (AraC), all compounds employed during T-ALL therapy,19 in combination with MPA, a pan AKR1C inhibitor.15,26 As expected, inhibition of AKR1C1-3 by MPA dramatically reduced AKR1C-dependent enzymatic activity as assessed by measurement of coumberone conversion (Suppl.