The promyelocytic leukaemia (PML) protein was first identified as part of the t(15∶17) chromosomal translocation found in patients with the disease acute promyelocytic leukaemia (APL) (de Thé et al., 1990) where it is fused to the retinoic receptor alpha (RARα). The gene discussed is PML; the disease is acute promyelocytic leukemia.