VAV1 and Increased total leukocyte count: Thus, consistent with the hypo-cellularity of the BM and increased mononuclear infiltration of the liver (Figure 2B), the VAV1-Cre-induced CBL/CBL-B DKO mice exhibited impaired BM hematopoiesis and enhanced hepatic extramedullary hematopoiesis, while the latter is apparently the primary source of peripheral leukocytosis.