HDAC9 and neoplasm: HDAC8, the first HDAC whose 3D structure was elucidated by X‐ray crystallography, is ubiquitously expressed in cells, localized within both the nucleus and cytoplasm, and is a zinc‐dependent class I HDAC comprising 377 amino acids.[36] HDAC8 preferentially interacts with H3K9 and H3K27, deacetylating these residues and regulating the transcription of target genes implicated in the development of tumor and immune evasion.[30, 37, 38, 39]