Table 1.

Histone chaperones in breast cancer metastasis

S. no	Histone chaperone	Role in breast cancer metastasis	References
1.	APLF	APLF over-expression is associated with breast cancer metastasis Regulate MacroH2A.1 recruitment in EMT specific promoter, EZH2/H3K27me3 level at FOXA1 promoter and recruitment of FOXA1 at CDH1 promoter	[40]
2.	HJURP	Higher expression in breast cancer metastasis condition Target of ATM signaling pathway, where it interacts with hMSH5 and NBS1	[43, 44, 46, 47]
3.	DAXX	Down-regulated in breast cancer metastasis Forms complex with ATRX in order to maintain H3K9me3 methylation Negative regulator of c-met DAXX knockout cells have lower H4 acetylation and higher HDAC2 activity Binds at the promoter region of RAD51	[50, 52, 53]
4.	DEK	Act as proto-oncogene Higher expression in breast cancer metastasis condition DEK knock down cells has lesser H3K9me3 mark, lower CDH1 expression. Induces metastasis via β-Catenin pathway Downstream target of RON Also found to mediate EMT via PI3K/AKT/mTOR pathway Causes angiogenesis via VEGF pathway	[55, 58, 60, 61, 63]
5.	ANP32E	Positive correlation with breast cancer metastasis Helps in the removal of H2AZ variants so that FACT can deposit ɣH2AX in response to DDR Influences E2F1 transcription factor Regulation by mi-RNA-141 Part of “Landmaine’s six gene signature” for predicting lung metastasis of breast cancer	[69, 71, 73]
6.	ASF1	ASF1B over-expressed in breast cancer metastasis	[75]
7.	FACT	Upregulated in breast cancer metastasis patient samples	[79]
8.	NPM1	Higher NPM1 expression among TNBC patients NPM1 expression more in basal breast cancer than luminal breast cancer samples NPM-1 regulates YY1 expression which causes suppression of c-FOS expression, hence promoting cell growth	[80, 82–84, 86]