Corresponding to this observation, S100A2 has also selleck chem been proposed as a tumor suppressor in early stage lung carcinogenesis. We recently performed mass spectrometry analysis of the extracellular matrix of whole breast tissue with the goal of determining underlying differences in the normal breast microenvironment between premenopausal African and Caucasian American women. Premenopausal African American women suffer disproportionately from breast cancer mortality compared to Caucasian women. Both social and biological mechanisms are contributory, including a higher prevalence of aggressive basal like breast cancers in African American women. Hornerin, an S100 protein family member, was detected in signifi cantly higher abundance in the Caucasian Inhibitors,Modulators,Libraries American samples.

Therefore we further investigated the biological functions of this protein, only to find that little is known. Hornerin was first characterized in the mouse embryo epidermis and was also detected in the skin, tongue, and forestomach of the adult tissues examined. Hor nerin contains a Ca2 binding EF hand domain Inhibitors,Modulators,Libraries at the N terminus followed by a spacer sequence and an extensive repetitive domain rich in glycine and serine. Its similarity in structural features, expression profile, exten sive posttranslational proteolytic processing, and tissue localization to profilaggrin indicated a role in keratino cyte cornification. Additional studies Inhibitors,Modulators,Libraries demonstrated the presence of hornerin in regenerating, psoriatic and healthy human skin, and that hornerin is a component of cornified cell envelope.

While it might initially seem pecu liar that a protein Inhibitors,Modulators,Libraries involved in cornification of the skin is found in breast tissue, it is important to recall the evolu tionary development of the mammary gland. In all Inhibitors,Modulators,Libraries mam mals, the mammary gland organogenesis arises from a localized thickening of the epidermis. An elevation of the epidermal mammary crest and the development of a milk line on both sides of the mid ventral line of the embryo form the mammary buds, which eventually pro gress to form the functional mammary gland. Indeed, other proteins involved in epidermalskin func tion have been shown to perform roles in mammary gland physiology. Neuregulin3 regulates the cell fate of pluripotent epidermal cells, including those that ultim ately differentiate into progenitor cells of the mammary gland.

Additionally, LMO 4 a member of the LIM only family of transcriptional co regulatory proteins functions in both epidermal cell migration and mam mary gland differentiation. mostly Herein, we demonstrate hornerin expression in human breast tissue and mammary epithelial and stromal cells, its regulation throughout postnatal mammary develop mental stages in murine tissue, as well as its expression in correlation with breast cancer subtypes.