Silent information regulator 2 homolog 1 (Sirtuin-1 or SIRT1) is a histone deacetylase (HDAC) class III dependent on NAD+ that is linked to genome stability, apoptosis and autophagy, senescence, cell proliferation, and aging, which is why it is important both in healthy hematopoiesis and in hematologic malignancies. The gene discussed is SIRT1; the disease is hematologic disorder.