SDC3 (syndecan-3) is a cell surface heparan sulfate proteoglycan with diverse regulatory functions across multiple biological processes. In the immune system, SDC3 positively regulates macrophage pro-inflammatory functions, with genetic ablation leading to impaired cytokine secretion, reduced phagocytosis, and compromised T cell effector responses 1. The protein is expressed by tumor-associated macrophages and Kupffer cells in fibrotic liver tissue, suggesting roles in inflammation and tissue remodeling 2. In neural development, SDC3 controls the timing of cerebellar granule cell precursor differentiation by regulating the transition from cell cycle exit to initial differentiation stages 3. Clinically, SDC3 has emerged as a biomarker in several diseases: reduced expression is associated with apparent treatment-resistant hypertension 4, while increased expression correlates with childhood obesity parameters including BMI, insulin levels, and HOMA-IR index 5. Additionally, SDC3 serves as a prognostic biomarker in osteosarcoma, with higher expression linked to poor outcomes 6. These findings establish SDC3 as a multifunctional regulator involved in immune responses, neural development, and metabolic disorders, with potential therapeutic implications across diverse pathological conditions 7.