H1-2 (H1.2 linker histone) is a chr6 structural protein that plays critical roles in chr6 compaction, gene regulation, and disease pathogenesis. H1-2 binds to linker DNA between nucleosomes and is essential for condensing nucleosome chains into higher-order chr6 fibers, with its absence causing global chr6 decompaction not observed with other H1 variants 1. The protein functions as a histone reader, specifically recognizing and binding H3K27me3 marks, which governs its recruitment to target chr6 regions 1. H1-2 acts as a gene-specific transcriptional regulator, repressing growth suppressive genes including p16 through direct promoter binding 12. In cancer, H1-2 demonstrates dual roles: it functions as a tumor suppressor in B-cell lymphomas where loss-of-function mutations drive malignant transformation through 3D genome reorganization and developmental gene derepression 3, while in solid tumors like pancreatic and lung cancers, H1-2 overexpression promotes metastasis and chemoresistance through mechanisms including c-MYC regulation and NRF2-mediated antioxidant responses 45. H1-2 also regulates metabolic processes, acting as a brake on white adipose tissue browning through IL10 receptor signaling 6, and contributes to neurodegenerative disease pathology through abnormal interactions with mutant FUS protein 7.