Taken together, these results indicate that reduction of Hdac2 in absence of Hdac1 (Hdac1Δ/Δ; Hdac2Δ/+) impacts Eμ-myc tumorigenesis by reducing the Eμ-myc-induced blasts in the BM, resulting in reduced circulating tumor cells and eventually delays Eμ-myc tumorigenesis (Fig. 2). The gene discussed is HDAC2; the disease is neoplasm.