Although IGHV1 is most frequently found in the CLL clones from all these mouse models, the preferential use of IGHV5 and IGHV14 by the Traf2DNxBCL2-tg+/+ CLL/SLL clones instead of the use of IGHV11 and IGHV12 seen in the other CLL mouse models might indicate that the CLL/SLL developed by the Traf2DNxBCL2-tg+/+ mice arises from a B cell subset different to that of the other CLL mouse models (see below). Here, IGHV1-2 is linked to B-cell chronic lymphocytic leukemia.