This antibody reacts with the human Syndecan-1 (CD38) protein. On western blots, a single band at ~90 kDa representing the glycosylated form of CD138; occasionally a band of ~31 kDa representing the un-glycosylated form of CD138 may be observed. Reactivity has been confirmed with human T47D, SW-480, and PC-3 cell lysates by western blotting and with formalin-fixed, paraffin-embedded (FFPE) human gastric cancer and breast cancer tissues, and mouse and rat stomach, small bowel, and skin tissues by immunohistochemistry. For best results in immunohistochemistry with formalin-fixed, paraffin-embedded (FFPE) tissues, heat induced epitope retrieval (HIER) with EDTA, pH 8.0, is required prior to staining.
Syndecans 1-4 are heparan sulfate proteoglycans (HSPGs), which are cell-surface-associated transmembrane proteins. Syndecans contain a small core protein with distinct functional domains to which are linked multiple glycosaminoglycan (GAG) chains, predominantly of the heparan sulfate variety. Syndecan synthesis is highly regulated and is dependent on both cell type and developmental state. Syndecans are involved in cell adhesion, tissue morphogenesis, and differentiation and regulation of cell responsiveness to soluble growth-regulatory compounds. These functions are attributed primarily to the glycan moieties. Syndecans also interact with growth factors such as fibroblast growth factor and epidermal growth factor. Syndecan-1 (CD138) is the prototypical member of the syndecan family, and can bind a variety of cytokines and modulate their activity, as well as the activity of extracellular matrix components and influence many developmental processes. CD138 is expressed on epithelia, pre-B cells, and plasma cells and can be detected even on fibroblasts, vascular smooth muscle cells, and endothelial cells. CD138 is mainly expressed in differentiating keratinocytes and is transiently upregulated in all layers of the epidermis upon tissue injury. CD138 is also expressed by human myeloma cell lines, where it mediates cell-cell adhesion, adhesion to type I collagen, and inhibition of invasion into type I collagen gels. Cells that normally invade type I collagen gels are rendered non-invasive after their transfection with CD138 cDNA, showing that loss of CD138 expression on the cell surface may be essential for the process of multiple myeloma (MM) cell invasion. CD138 is shed from myeloma cells and accumulates in the serum of myeloma patients. Shed CD138 accumulates within the extracellular matrix of the marrow and may play a critical role in promoting myeloma pathogenesis, or in regeneration of the tumor after chemotherapy. Soluble CD138 may participate in the pathology of myeloma by modulating cytokine activity within the bone marrow, and may be and important prognostic factor in MM. CD138 is a functional co-receptor for hepatocyte growth factor (HGF) that promotes HGF/Met signaling in MM cells, suggesting a novel function for CD138 in MM tumorigenesis. The level of CD138 expression is a distinguishing feature between keratoacanthoma and invasive cutaneous squamous cell carcinoma. E-cadherin and CD138 act in concert to stabilize the epithelium; loss of both of these adhesion molecules is associated with malignant transformation. CD138 is also a prognostic marker for laryngeal cancer and a sensitive marker for plasmacytoma. CD138 expression is upregulated in pancreatic but not other gastrointestinal cancers. Epithelial and stromal CD138 expression is a predictor of outcome in patients with gastric cancer. CD138 is expressed at high levels in both breast cancer tissues and cell-lines when compared with normal breast tissues, and expression is induced in the stroma of infiltrating breast carcinoma. In breast carcinoma, relative expression levels of CD138 and syndecan-4 regulate fibroblast growth factor receptor binding. So upregulation and downregulation of CD138 on the cell surface often correlates with the gain of cancerous characteristics and serum levels of the shedded soluble sCD138 are used as a prognostic factor of cancerogenesis.
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Protein Aliases: CD antigen 138; CD138; CD138 antigen; heparan sulfate proteoglycan fibroblast growth factor receptor; SDC; SDC1; SYND1; syndecan proteoglycan 1; Syndecan-1; synstatin
Gene Aliases: AA408134; AA409076; CD138; HSPG; SDC; SDC1; Sstn; syn-1; Synd; Synd-1; SYND1; SYNDECA; Syndecan
Molecular Function: cell adhesion molecule cytoskeletal protein defense/immunity protein extracellular matrix glycoprotein extracellular matrix protein membrane-bound signaling molecule signaling molecule