Expression of epimorphin in normal and diseased human skin. Immunohistochemical and immunoblot detection

Epimorphin has been recently identified as a mesenchymal, extracellular protein which regulates epithelial morphogenesis and which is essential for epithelial/mesenchymal interaction in mouse tissues. In this study, our aim was to determine whether this novel protein is expressed in normal and diseased human skin and, its staining pattern. The expression of epimorphin was examined immunohistochemically in 68 specimens including 15 normal and 53 diseased skin specimens and some of them were further analyzed by Western immunoblot with anti-epimorphin monoclonal antibody (MC-1). Epimorphin was constitutively expressed in all of the normal skin tissue specimens. It was localized typically in a linear pattern at the basement membrane zone and in the collagenous tissue around hair follicles, vessels and sweat glands. An increased expression was observed in all of the diseased skin specimens in contrast to the normal ones. In skin ulcer and scar, epimorphin was intensely labelled in the upper to middle dermis. In cutaneous tumors, including basal cell carcinoma, squamous cell carcinoma, Bowen's disease and trichilemmoma, epimorphin was most intensely expressed in the collagenous tissue surrounding tumour nests and in all dermal layers near the tumors. The presence of the molecule in human skin tissue was shown as a 150 kDa protein with MC-1 by immunoblot. These findings showed the ubiquitous presence of epimorphin in a stable pattern in normal skin tissue and its markedly increased expression in diseased skin tissue particularly in neoplastic tumors. Further study is required to elucidate the physiological role of epimorphin in normal and diseased skin.