S100A7, also known as Psoriasin, belongs to the S-100 family of calcium binding proteins and is secreted via a non-classical secretory pathway into the cytoplasm. It is thought to function in the regulation of many cellular processes, including the cell cycle, cell progression and cellular differentiation. It contains two EF-hand domains and is highly upregulated in psoriatic epidermis, as well as in bladder squamous cell carcinoma and breast cancer tissue, suggesting a possible role in carcinogenesis.