S100A7, also known as Psoriasin, is an acetylated EF hand calcium and zinc binding protein. It is upregulated in keratinocytes of psoriasis and atopic dermatitis lesions, as well as in epithelial cells of the tongue, eye, and female genital tract. Its upregulation can be induced by bacterial exposure, inflammatory cytokines, or epidermal barrier disruption. S100A7 supports epithelial integrity by sequestering zinc from E. coli and by inducing the upregulation of tight junction proteins. The interaction of S100A7 with RAGE promotes the migration of immune cells and the infiltration of macrophages into tumor sites.