PRMT3 is a type I protein arginine methyltransferase that catalyzes monomethylation and asymmetric dimethylation of arginine residues in target proteins 123. Primary functions include methylation of ribosomal proteins, particularly uS5/RPS2 1, and histone H4 at Arg-3 to promote transcriptional activation and osteogenesis 34. PRMT3 also regulates retinoic acid signaling by inhibiting ALDH1A1 activity through protein-protein interaction 5. Mechanistically, PRMT3 mediates asymmetric dimethylation of diverse substrates including IGF2BP1 6, METTL14 7, HSP60 8, and PDHK1 9, modulating their functions in cancer-relevant pathways. Clinically, PRMT3 is implicated in multiple malignancies. In hepatocellular carcinoma, PRMT3 drives oxaliplatin resistance through IGF2BP1 methylation 6, promotes immunotherapy resistance via HSP60-mediated mitochondrial dysfunction 8, and enhances immune evasion through PDHK1-regulated glycolysis and PD-L1 expression 9. In endometrial carcinoma, PRMT3 inhibition sensitizes cells to ferroptosis and immunotherapy 7. PRMT3 also drives glioblastoma progression via HIF1A-mediated metabolic rewiring 10. PRMT3 represents an emerging therapeutic target, with both inhibitors and proteolysis-targeting chimeras showing promise in preclinical models 1112.