Trisenox, an injectable form of ATO, used in conjunction with ATRA, was approved by the United States (US) Food and Drug administration (FDA) in 2018 for the treatment of adults with newly diagnosed low-risk APL characterized by the presence of the t(15;17) translocation or promyelocytic leukemia/retinoic acid receptor alpha (PML/RARα) gene expression [5]. The gene discussed is RARA; the disease is acute promyelocytic leukemia.