Based on limited published evidence, H2BC18 is a core histone protein functioning as a structural constituent of chr1 and nucleosomes. It regulates DNA accessibility through chr1 organization and post-translational modifications, playing central roles in transcription, DNA repair, replication, and chr1 stability. H2BC18 localizes to the nucleus and nucleoplasm. Recent studies identified H2BC18 as a key gene in Graves' orbitopathy pathogenesis 1 and as a prognostic marker in colorectal cancer with potential involvement in malignant progression 2.