The function of ING4 (inhibitor of growth family member 4, ENSG00000111653) is as follows. Component of HBO1 complexes, which specifically mediate acetylation of histone H3 at 'Lys-14' (H3K14ac), and have reduced activity toward histone H4 (PubMed:16387653). Through chromatin acetylation it may function in DNA replication (PubMed:16387653). May inhibit tumor progression by modulating the transcriptional output of signaling pathways which regulate cell proliferation (PubMed:15251430, PubMed:15528276). Can suppress brain tumor angiogenesis through transcriptional repression of RELA/NFKB3 target genes when complexed with RELA (PubMed:15029197). May also specifically suppress loss of contact inhibition elicited by activated oncogenes such as MYC (PubMed:15029197). Represses hypoxia inducible factor's (HIF) activity by interacting with HIF prolyl hydroxylase 2 (EGLN1) (PubMed:15897452). Can enhance apoptosis induced by serum starvation in mammary epithelial cell line HC11 (By similarity). {ECO:0000250|UniProtKB:Q8C0D7, ECO:0000269|PubMed:15029197, ECO:0000269|PubMed:15251430, ECO:0000269|PubMed:15528276, ECO:0000269|PubMed:15897452, ECO:0000269|PubMed:16387653}.