S100A13 is a calcium-binding protein that functions as a critical component of a copper-dependent export pathway for signal peptide-lacking secreted proteins 1. Structurally, S100A13 belongs to the S100 protein family, with sequence homologies ranging from 50.5-59.3% to other S100 members, and is highly expressed in skeletal muscle, heart, kidney, ovary, small intestine, and pancreas 2. The primary function of S100A13 is mediating copper-dependent, stress-induced release of interleukin-1α (IL-1α) and fibroblast growth factor-1 (FGF-1) 1. S100A13 acts as a key cargo protein promoting FGF-1 release from endothelial cells, though it does not affect FGF-1 transportation to the cell membrane 3. This export mechanism is distinct from classical signal peptide-dependent pathways. Disease relevance spans multiple conditions. S100A13 overexpression in thyroid cancer cell lines (TT cells) accelerates cell proliferation and promotes cell cycle progression 4, and S100A13 expression correlates with HMGA1 in modulating thyroid cancer growth and invasion 5. S100A13 may contribute to angiogenesis in endometriosis through FGF-1-dependent pathways 6. Notably, in Alzheimer's disease, S100A13 is upregulated in disease contexts despite being downregulated by APOE-ε4, suggesting a disease-response mechanism 7. In glioblastoma, S100A13 associates with microglial dysfunction within the tumor microenvironment 8.