S100A7 (psoriasin) is a calcium-binding protein primarily expressed in epithelial cells that functions as both an intracellular signaling molecule and secreted immune mediator 1. Mechanistically, S100A7 acts through multiple pathways: intracellularly via JAB1 interaction to modulate p27Kip1-dependent proliferation 2, and extracellularly through RAGE receptor binding to activate ERK and FAK signaling 3. S100A7 exhibits potent chemotactic activity for neutrophils and other hematopoietic cells, promoting neutrophil extracellular trap (NET) formation through ROS elevation 4. In inflammatory skin diseases, S100A7 expression correlates with TH2/TH22 cytokine activation and keratinocyte proliferation, distinguishing acute from chr1 atopic dermatitis and psoriasis 56. Clinically, S100A7 dysregulation associates with multiple malignancies: in cervical cancer, it drives lymph node metastasis via NET-mediated mechanisms 4; in esophageal squamous cell carcinoma, elevated serum S100A7 serves as an independent prognostic biomarker and diagnostic indicator 3; and in breast cancer, it marks progression toward invasive phenotypes 7. S100A7 also promotes tumor microenvironment remodeling through M2 macrophage infiltration and angiogenesis 3, establishing it as both a disease biomarker and potential therapeutic target.