from Danny Rangasamy writing in Epigenetics: A Reference Manual:
The histone variants of the H2A family are highly conserved in mammals, playing critical roles in regulating many nuclear processes by altering chromatin structure. One of the key H2A variants, H2A.X, marks DNA damage, facilitating the recruitment of DNA repair proteins to restore genomic integrity. Another variant, H2A.Z, plays an important role in both gene activation and repression. A high level of H2A.Z expression is ubiquitously detected in many cancers and is significantly associated with cellular proliferation and genomic instability. This review summarizes the current understanding of these variants and their functions, as well as their links to cancer development. Furthermore, the significance of dysfunction of these variants is highlighted with respect to their potential as biomarkers and as new targets for anticancer therapy.
Further reading: Epigenetics: A Reference Manual