All Eμ-PRMT5/TCL1 mice between ages 6–15 months became visibly ill and developed a neoplasia with a similar CLL-like immunophenotype to Eμ-TCL1 mice; although Eμ-PRMT5/TCL1 mice frequently presented with large cells circulating in the blood (FSChigh), a rare event in Eμ-TCL1 mice (Supplemental Fig. 3A, B). Here, TCL1A is linked to neoplasm.