In this early work the Reh and NALM-6, two B cell acute lymphoid leukemia phenotypically resembling a pre-B developmental stage, displayed efficiency of recombination evaluated as 21.6 and 1.8% respectively; the SUP-T1 non-Hodgkin’s lymphoma, double-positive for CD4 and CD8, scored as 0.09% while the acute myelogenous leukemia HL-60 and the chronic myelogenous leukemia K-562 scored at 0.008 and 0.02% respectively (Gauss et al., 1998). The gene discussed is CD4; the disease is acute myeloid leukemia.