Rearrangements of the RARG gene, rather than of the RARA gene, have been identified in acute promyelocytic leukemia patients and involved the NUP98 (for nucleoporin, 3 patients), CPSF6 (encodes an RNA-binding protein, 4 patients), NPM1 (for nucleophosmin, 1 patient), and PML (1 patient) genes. The gene discussed is NPM1; the disease is acute promyelocytic leukemia.