Histone deacetylase 2 (HDAC2) is an enzyme that in humans is encoded by the HDAC2 gene. It belongs to the histone deacetylase class of enzymes responsible for the removal of acetyl groups from lysine residues at the N-terminal region of the core histones (H2A, H2B, H3, and H4). As such, it plays an important role in gene expression by facilitating the formation of transcription repressor complexes and for this reason is often considered an important target for cancer therapy. Though the functional role of the class to which HDAC2 belongs has been carefully studied, the mechanism by which HDAC2 interacts with histone deacetylases of other classes has yet to be elucidated. HDAC2 is broadly regulated by protein kinase 2 (CK2) and protein phosphatase 1 (PP1), but biochemical analysis suggests its regulation is more complex (evinced by the coexistence of HDAC1 and HDAC2 in three distinct protein complexes). HDAC2 has been shown to play a role in cardiac hypertrophy, Alzheimer's disease, Parkinson's disease, acute myeloid leukemia (AML), osteosarcoma, and stomach cancer.