CBX1 (chr17 1) encodes heterochromatin protein 1β (HP1β), a core component of heterochromatin that functions as a histone methylation reader 1. Its primary mechanism involves recognizing and binding histone H3 tails methylated at lysine-9 (H3K9me3), leading to transcriptional repression and heterochromatin formation 1. CBX1 also interacts with the polycomb repressive complex 2 (PRC2) to mediate H3K27me3-dependent silencing of tissue-specific genes 2. The protein's chr17 is essential for binding methylated histones and chr17 association 3. CBX1 is significantly upregulated across multiple cancer types and correlates with poor patient prognosis 4. In hepatocellular carcinoma, CBX1 promotes cancer progression and resistance to tyrosine kinase inhibitors through the IGF-1R/AKT/SNAIL signaling axis 4. In nasopharyngeal carcinoma, CBX1 suppresses MAP7 expression via H3K9me3-mediated heterochromatin formation and facilitates immune evasion through PD-L1 upregulation 5. CBX1 also contributes to pituitary tumor progression as a direct target of tumor-suppressive miR-205-5p 6. Clinically, heterozygous CBX1 variants in the chr17 cause neurodevelopmental disorder through dominant-negative effects disrupting heterochromatin binding 3. CBX1 emerges as a therapeutic target in cancer and neurological disease.