A 2018 study investigated the possible co-operation of Ezh2 with Runx1 in dual knockout mice compared with individual knockouts and wild type.87 While all three knockout models (both individual knockouts and the double knockout) developed leukopenia, only dual inactivation of both Ezh2 and Runx1 resulted in a significant increase in the number of immature T cells (CD4–/CD8–/CD44+/CD25–/Kit+/Flt3+) and DN2 cells (CD4–/CD8–/CD44+/CD25+). Here, CD44 is linked to Decreased total leukocyte count.