Psoriasin (S100A7)

Abstract

Psoriasin (S100A7) is a relatively new member of the S100 gene family that is located within the S100 gene cluster on chromosome 1q21 and shares the typical calcium binding domains that define this family of proteins. It was first identified as a 11.4 kDa cytoplasmic and secreted protein isolated from skin involved by psoriasis, which can be induced in cultured squamous epithelial cells. It is now known to be expressed by both normal cultured and malignant keratinocytes and malignant breast epithelial cells within ductal carcinoma in situ, suggesting an association with abnormal pathways of differentiation. Current evidence supports a role in the pathogenesis of inflammatory skin disease, as a chemotactic factor for hematopoietic cells, and a role in early stages of breast tumor progression in association with the development of the invasive phenotype. While therapeutic potential as a target for modulation of the inflammatory response in psoriasis awaits further studies, potential clinical applications already include a role as a detection marker for squamous cell carcinoma and a diagnostic marker to distinguish in situ from invasive breast cancer cells.

IL-22 Inhibits Epidermal Differentiation and Induces Proinflammatory Gene Expression and Migration of Human Keratinocytes

“…S100A7, S100A8, and S100A9 belong to the pleiotropic S100 family of calcium-binding proteins (26). Although their main functions are as yet unclear, they appear to play prominent inflammatory functions (26,36,37) and to be involved in the fine regulation of a large number of intraand extracellular activities such as the dynamic of motility of cytoskeletal components or chemotaxis (38). Interestingly, whereas all three S100A7, S100A8, and S100A9 proteins have been reported to be expressed at low or undetectable levels in normal skin epidermis and nondifferentiated cultured keratinocytes, they are expressed highly in abnormally differentiated psoriatic keratinocytes (39) during wound repair (40) and in epithelial skin tumors (37,41,42).…”

Suction blister fluid as potential body fluid for biomarker proteins

“…Interestingly, upregulated levels of beta-2-microglobulin, C-reactive protein, and psoriasin have been found in psoriatic skin biopsies [37][38][39]. Additionally, in abnormal differentiation of epithelial cells like skin cancers, upregulated levels of psoriasin have also been demonstrated [39]. A preliminary study on psoriatic skin in which psoriasin was identified as up regulated protein in suction blister fluid demonstrates the usefulness of this body fluid [40].…”

Psoriasin (S100A7) increases the expression of ROS and VEGF and acts through RAGE to promote endothelial cell proliferation

“…The expression of psoriasin was shown to correlate with features of poor prognosis, including estrogen receptor (ER) and progesterone receptor (PR) negativity, HER2 positivity and the presence of lymphocytic infiltration [9][10][11].…”