CCL4 (C-C motif chemokine ligand 4) is a CC chemokine that functions primarily as an immune regulator and inflammatory mediator. Mechanistically, CCL4 exerts its effects through binding to chemokine receptors, particularly CCR5, and can interact with related chemokines such as CCL3 and CCL5 1. CCL4 promotes chemotaxis and cell-cell signaling, facilitating immune cell recruitment and activation 2. The protein contributes to diverse pathological processes: in aging-related vascular dysfunction, CCL4 elevates reactive oxygen species and endothelial inflammation, impairing angiogenic capacity 3. In eosinophilic airway inflammation, CCL4 promotes eosinophil survival by inducing MUC1 N-terminal domain shedding on epithelial cells 4. Regarding cancer, CCL4's role is context-dependent: it can promote tumor progression by recruiting regulatory T cells and pro-tumorigenic macrophages 1, yet also enhance anti-tumor immunity through cytolytic lymphocyte recruitment 2. CCL4 gene polymorphisms influence disease susceptibility; specific variants are associated with reduced hepatocellular carcinoma and breast cancer metastasis risk 56. Clinically, CCL4 represents a potential therapeutic target, with CCR5 antagonists under investigation for cancer treatment, though context-specific efficacy requires careful evaluation.