In null cell lymphomas and CD34-positive leukaemias there may be a genuine absence of IgH or TCRγ loci rearrangements since null-cell lymphomas may actually be NK cell tumours (van Dongen et al., 2003, Ponce et al., 2010), and CD34-positive leukaemias may represent expansions of immature B-cells that have not completed V(D)J recombination. The gene discussed is CD34; the disease is leukemia.