We first compared the incidence and rate of pre-B/B-cell lymphoma development in Eμ-Myc, Eμ-Myc;CD19-Cre, Eμ-Myc;CD19-Cre;Mcl-1fl/+ and Eμ-Myc;CD19-Cre;Mcl-1fl/fl mice (Figure 1a). The gene discussed is CD19; the disease is B-cell non-Hodgkin lymphoma.