CYP26A1 and acute promyelocytic leukemia: This scenario, of muted ATRA efficacy due to high CYP26 activity, has also been documented in APL (59) and has prompted the development of a class of CYP26 inhibitors, also known as retinoic acid metabolism blocking agents (RAMBAs), that have the potential to prolong the half-life of pharmacologically administered ATRA when used as adjuvant therapy in refractory patients (60).