Acute promyelocytic leukemia (APL) is a sub-type of acute myeloid leukemia (AML) distinguished by a differentiation block at the promyelocytic stage and the largely predominant t(15;17) chromosomal translocation generating the PML-RARα fusion protein (Ablain & de The, 2011). The gene discussed is RARA; the disease is acute promyelocytic leukemia.