MCL1 and lymphoma: Western blot analysis revealed that many lymphomas from Eμ-Myc;CD19-Cre;Mcl-1fl/+(3/3 tested) and Eμ-Myc;CD19-Cre;Mcl-1fl/fl mice (2/3 tested) retained MCL-1 expression, but its levels were significantly lower than in lymphomas from Eμ-Myc control mice (Figure 2a).