CD19 and lymphoma: Surprisingly, we found that lymphoma development in the Eμ-Myc;CD19-Cre;Mcl-1fl/+ and Eμ-Myc;CD19-Cre;Mcl-1fl/fl mice was only slightly slower than in the control Eμ-Myc and Eμ-Myc;CD19-Cre mice.