MAPK3 and Increased total leukocyte count: While Tet2fl/flTet3fl/flCre-ERT2 mice developed progressive leukocytosis characterized by massive expansion of myeloid-lineage cells as early as 3–7 weeks after tamoxifen injection [50], Tdgfl/flCre-ERT2 mice were healthy and showed only a slight (not significant) increase in the myeloid population (CD11b+ Gr-1+) with a slight (not significant) decline in T and B cells in the peripheral blood at 1 year after tamoxifen injection (Fig. 6D–F).