HDAC1 is a member of the histone deacetylase/acuc/apha family and a component of the histone deacetylase complex. HDAC1 is in charge of the deacetylation of lysine residues on the N-terminal part of the core histones（H2A， H2B， H3 and H4). Histone acetylation and deacetylation， catalyzed by multi-subunit complexes， are a crucial factor in the regulation of eukaryotic gene expression. In addition， HDAC1 interacts with retinoblastoma tumor-suppressor protein and this complex is a major factor in the control of cell proliferation and differentiation. Low levels of HDAC1 were linked to breast cancer progression. Studies have shown that cancer cells successfully maintained decreased levels of pyruvate to prevent inhibition of HDAC1/HDAC3 and thus to escape cell death. HDAC1 is over-expressed in diffuse large B-cell lymphoma and peripheral T-cell lymphoma in opposite to normal lymphoid tissue. The tissue specificity of HDAC1 is ubiquitous， with higher levels in the heart， pancreas and testis， and lower levels in the kidney and brain.
