ChIP assays were conducted following the manufacturer’s instructions (Millipore). Antibodies against H3K4me1, H3K4me2, H3K4me3, H3K9me2, H3K9me3, H3K36me3, H3K27me3, G9a, DNMT1 or E2F1 were utilized for ChIP. RT-PCR was performed with specifically designed qPCR primers targeting the proximal promoter region of TP53BP2. IgG was used as a negative control to measure nonspecific background signals via immunoprecipitation. The resulting amplified product was evaluated through electrophoresis, and the signals were quantified as a percentage of the input. The primer sequences are provided in Table S3.