TET2 and Increased total leukocyte count: The resulting mice (Tet2fl/fl) were then crossed with transgenic Vav-Cre mice, resulting in Tet2 deletion in the hematopoietic system in utero, leading to the development of a CMML-like disease by 20 weeks of life with monocyte–predominant leukocytosis and splenomegaly.