Monoclonal Antibody to Keratin Filaments, Specific for Glandular Epithelia and Their Tumors. Use in Surgical Pathology

A monoclonal antibody (RGE 53) against keratin intermediate filaments was prepared by fusing myeloma cells with splenic lymphocytes from mice immunized with a HeLa cell cytoskeleton preparation and human callus keratins. The antibody, selected for fibrillar staining in HeLa cells and a negative reaction on human skin, was tested on frozen sections from normal and malignant human tissues. RGE 53 specifically recognizes glandular epithelial cells from female breast, digestive, respiratory, and urogenital tracts, endocrine and exocrine tissues, and mesothelial cells. No reaction is found in stratified squamous epithelia or nonepithelial tissues. Furthermore, RGE 53 can distinguish adenocarcinomas and mesotheliomas, which stain positively in the indirect immunofluorescence technique from squamous cell carcinomas and nonepithelial tumors, which are negative for this antibody. RGE 53 may, therefore, be a useful tool for differential diagnosis in surgical pathology, especially in those cases in which anaplastic carcinomas have to be characterized.