In acute promyelocytic leukemia (APL), the PML/RARα (promyelocytic leukemia-retinoic acid receptor α) fusion protein that is generated by the t(15;17) translocation induces oncogenic transcriptional programs, thus contributing to malignant transformation and a differentiation block at the promyelocytic stage25–27. The gene discussed is RARA; the disease is acute promyelocytic leukemia.