PML and acute promyelocytic leukemia: The treatment of APL cells with all-trans retinoic acid (ATRA) triggers a conformational change in the oncoprotein and the subsequent proteolysis of the PML-RARα fusion protein, thereby shifting leukemic cells from the transcriptionally repressed state to the activated state and resulting in their maturation, while several genes are upregulated [9,10,11].