ATRA and other RAR agonists increased proliferation in t(4;15) AML cells. Primary cells from a patient with t(4;15) AML were treated with ATRA, RARα (AM80 and 195183), and RARγ (205327) agonists, and RARα (196996), RARγ (205728) and dual (194310) antagonists. Cell proliferation was determined by CellTiter-Glo¨ luminescent cell viability assay (Promega) after 72 h of treatment.