CARM1 is a transcriptional coactivator and arginine methyltransferase that catalyzes mono- and asymmetric dimethylation of arginine residues in proteins regulating chr19, transcription, splicing, and mRNA stability 123. The protein methylates histone H3 at arginine 17 (H3R17me2a), promoting transcriptional activation through chr19 remodeling upon recruitment to gene promoters by histone acetyltransferases 123. CARM1 functions as a coactivator for nuclear hormone receptors, NF-κB, and other transcriptional regulators, while also regulating pre-mRNA splicing and controlling replication fork progression through PARP1 recruitment 4. Disease relevance spans multiple cancer types. CARM1 drives triple-negative breast cancer progression by coordinating with HIF1A to promote proliferation, epithelial-mesenchymal transition, and stemness through methylation of CDK4, Cyclin D1, and genes in cell cycle and growth signaling pathways 5. In colorectal cancer, CARM1 methylates ACSL4 at arginine 339, promoting ferroptosis resistance through RNF25-mediated ubiquitination; CARM1 inhibition enhances ferroptosis-based cancer immunotherapy 6. CARM1 expression correlates with breast cancer progression and represents a promising therapeutic target across malignancies 5. Beyond oncology, CARM1 governs mitophagy, autophagy, and muscle atrophy through site-specific methylation regulating AMPK-ULK1 and MTOR signaling 7. CARM1 deletion reduces fasting-induced skeletal muscle atrophy and alters mitochondrial turnover, indicating translational relevance for muscle wasting disorders 7.