KDM4A (lysine demethylase 4A) is a histone demethylase that removes repressive H3K9me3 marks to regulate gene expression and chr1 accessibility 1. The enzyme localizes to telomeric repeats and maintains telomere integrity by regulating H3K9me3 levels at telomeres, with inhibition causing telomeric dysfunction and genomic instability 2. KDM4A promotes cellular senescence through multiple pathways: it upregulates AGT expression via H3K9me3 demethylation, leading to disrupted mitophagy and activation of cGAS-STING signaling 3, and contributes to cardiac fibrosis by promoting premature senescence in fibroblasts through Trim44-mediated autophagy suppression 4. In cancer, KDM4A exhibits context-dependent effects - it can promote tumor growth in squamous cell carcinoma, where its inhibition induces DNA replication stress and activates tumor-intrinsic immunity 5, and in bladder cancer by regulating cholesterol synthesis and oxidative stress balance 6. However, in colorectal cancer, KDM4A-induced senescence enhances immunotherapy efficacy by promoting CD8+ T-cell infiltration 3. KDM4A protein levels are posttranscriptionally elevated in acute myeloid leukemia samples with IDH1/2 mutations 7, highlighting its significance as a therapeutic target across multiple malignancies.