The histone H2B (formylK120) antibody is a specialized tool used to detect formylation on lysine 120 of histone H2B, a post-translational modification (PTM) implicated in chromatin dynamics and gene regulation. Histone H2B is a core component of nucleosomes, playing a structural role in DNA packaging and serving as a substrate for diverse PTMs that regulate processes like transcription, DNA repair, and apoptosis. Formylation, a less-studied histone modification, involves the addition of a formyl group to lysine residues. The formylK120 modification in H2B has recently gained attention for its potential role in DNA damage response pathways. Studies suggest it may act as a signaling mark during DNA double-strand break repair, possibly interacting with repair proteins or modulating chromatin accessibility. This antibody enables researchers to investigate the spatial and temporal distribution of H2B formylK120 using techniques like Western blotting, immunofluorescence, or ChIP-seq. Its specificity for the formylated lysine 120 epitope (rather than other H2B modifications, such as ubiquitination or acetylation) makes it valuable for dissecting the functional significance of this PTM. Validation typically includes peptide competition assays and testing in genetic models lacking formylation pathways. Ongoing research aims to clarify its crosstalk with other histone marks and its implications in diseases linked to genomic instability, such as cancer or neurodegenerative disorders.