While the large cells in Eμ-PRMT5/TCL1 mice maintained the Cd19+ /Cd5+ “CLL-like” phenotype, these cells were predominantly B220bright, a feature consistent with murine models of large cell lymphoma35, in contrast with B220dim expression observed on the “CLL-like” small cells in both Eμ-PRMT5 and Eμ-TCL1 mice. Here, TCL1A is linked to B-cell chronic lymphocytic leukemia.