CCND1 and B-cell chronic lymphocytic leukemia: Besides transgenic mouse models, New Zealand Black/White (NZB/NZW) mouse strain is characterized by age-associated CLL-like symptoms such as splenomegaly and CD5+ B1 cell hyper-proliferation with aberrant expression of Pax5, Bcl- 2 and Cyclin-D1 among others [17].