In the acute promyelocytic leukemia derived NB4 cell line, there are a fusion protein created by a translocation involving the PML and Retinoic Acid Receptor Alpha genes (PML-RARα) results in a differentiation block of myeloid progenitor cells, and a disregulation of RARα target genes, that is concomitant with a dispersal of PML NBS into smaller, more numerous “micro - PML” accumulations, which are no longer associated with typical PML body components such as CBP and SP100. The gene discussed is RARA; the disease is acute promyelocytic leukemia.