H2AC12 is a core histone component of nucleosomes that wraps and compacts DNA into chr6, regulating DNA accessibility for transcription, repair, replication, and chr6 stability. The protein localizes to the nucleus and nucleoplasm, functioning as a structural constituent of chr6 and participating in heterochromatin formation. Based on limited published evidence, H2AC12 peptide fragments were identified in salivary proteomes of glioblastoma patients and proposed as potential diagnostic biomarkers 1, though functional validation in this context remains preliminary.