These findings show a correlation between the coexpression of vimentin with K8 and K18 keratins and the invasive and metastatic behavior of three representative human melanoma cell lines.

The metalloproteinases, a multigene family of metal-requiring enzymes, have been suggested to play a role in tumor invasion and metastasis. Previously, we demonstrated that human primary prostate tumors express higher levels of matrilysin and gelatinase A mRNA than normal prostate does. In the study presented here, we used in situ hybridization and immunohistochemical staining of serial sections of paraffin-embedded primary prostate tumors to compare the sites of matrilysin and gelatinase A expression and protein localization. These results confirmed the epithelial nature of matrilysin expression and protein localization. In contrast, gelatinase A mRNA was localized to the interstitial stroma, whereas the protein was associated with the epithelial tumor cells. In situ hybridization was also used to demonstrate that gelatinase B expression was restricted to macrophages infiltrating the tumors. Proteins isolated from an additional set of frozen tumor specimens were analyzed by western blotting to determine the relative amounts of matrilysin in the active and proenzyme forms. The western analyses demonstrated that in all cases in which matrilysin was detected, at least some of the enzyme was in the active form. These results are discussed with respect to the possible role these enzymes may play in prostate tumor progression.

Three mouse monoclonal anti-human cytokeratin antibodies were made against human sole epidermis. One of these (KA4) was shown to react with a variety of human simple epithelium, including eccrine and apocrine sweat glands and the luminal cells of the breast ducts and lobules, but failed to decorate interfollicular stratified squamous epithelium. This antibody reacted by the immunoblot technic with cytokeratins of Mr values 54, 46, and 40 kdaltons. KA4 reacted strongly with clear cells found in 11% of breast epithelium in clinically uninvolved nipples and with all Paget's cells in four cases of mammary and five cases of extramammary Paget's disease. These findings suggest a common cellular phenotype for Paget's cells and relates them to a population of cells found in breast epithelium.

No abstract

The presence of intracellular keratin was examined in 230 human neoplasms using indirect immunofluorescence on fresh frozen, acetone-fixed sections. The use of antikeratin antibodies raised in rabbits against human callus and purified by affinity chromatography proved to be a rapid, sensitive, and reliable method of demonstrating keratin. Epithelial tissues and epithelial-derived neoplasms were found to contain keratin, whereas tissues and neoplasms of mesenchymal, lymphoreticular, or neural crest origin did not contain intracellular keratin. This technic is a useful adjunct for the surgical pathologist in the diagnosis of poorly differentiated neoplasms. Its application either confirmed, modified, or in several instances, changed the original light microscopic impression. The modified or changed diagnoses were confirmed by transmission electron microscopy.