MacroH2A – An epigenetic regulator of cancer

• MacroH2As are primarily tumor suppressive.
• MacroH2As establish and maintain differentiated states.
• The function of macroH2A1.2 is context-dependent.
• MacroH2A1.1 and macroH2A2 have potential as biomarkers for good prognosis.

Epigenetic regulation is one of the most promising and expanding areas of cancer research. One of the emerging, but least understood aspects of epigenetics is the facultative and locus-specific incorporation of histone variants and their function in chromatin. With the characterization of the first loss of function phenotypes of the macroH2A histone variants, previously unrecognized epigenetic mechanisms have now moved into the spotlight of cancer research. Here, we summarize data supporting different molecular mechanisms that could mediate the primarily tumor suppressive function of macroH2A. We further discuss context-dependent and isoform-specific functions. The aim of this review is to provide guidance for those assessing macroH2A’s potential as biomarker or therapeutic intervention point.