However, a majority of these CLL mouse models, including the profusely studied Eμ-T Cell Leukemia-1 (Eμ-TCL-1)-tg mice [reviewed in (21)], only produce UM-CLL clones, thus implying that M-CLL etiology is not properly represented in these mice. The gene discussed is TG; the disease is B-cell chronic lymphocytic leukemia.