This is a cocktail of four highly specific monoclonal antibodies (EGP40/826, EGP40/837, EGP40/1110, EGP40/1120) that recognize extracellular as well as intracellular domains of the epithelial cellular adhesion molecule (Ep-CAM). Epithelial specific antigen (ESA), or Ep-CAM, is a 40-43 kDa transmembrane epithelial glycoprotein expressed on the basolateral cell surface in most simple epithelia and a vast majority of carcinomas. This epithelial antigen plays an important role as a tumor-cell marker in lymph nodes from patients with esophageal carcinoma otherwise classified as node-negative. Epithelial antigen has also been suggested as a discriminator between basal cell and baso-squamous carcinomas, and squamous cell carcinoma of the skin. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.