title: Immunocytochemical and immunoelectron microscopic demonstration of cathepsin B in human malignant melanoma.
abstract: Proteases are known to enhance the spread of tumour cells. Possible sources of these proteases are the tumour cells themselves or fibroblasts in the tumour tissue. Immunological staining with anticathepsin B antibody indicates that the subcellular distribution of cathepsin B in tumour cell lines differs from that in normal liver. The aims of this study were: (i) to show whether different types of melanoma differ in their production of cathepsin B; (ii) to identify the cathepsin B-producing cells; and (iii) to determine the subcellular distribution of cathepsin B in melanoma cells. All types of melanomas contained cell regions stained with anticathepsin B antibody. The intensity of the stain and the number of cells reacting with anticathepsin B antibody depended on the size of the tumour but not on the type of melanoma. Epithelioid cells stained more intensely with anticathepsin B antibody than spindle-shaped cells. Cells staining with anticathepsin B antibody were almost exclusively tumour cells. Anticathepsin B stain was located mainly in vesicular structures which did not contain a filamentous matrix. Additional anticathepsin B stain was detected at the extracellular spaces. Hypomelanotic melanoma cells, mainly of the epithelioid type, produced most of the cathepsin B. Cathepsin B may be involved in both the degradation of possibly abnormal melanosomes and the focal degradation of the extracellular matrix.
authors.affiliation: Department of Anatomy, Eberhard-Karls-Universität, Tübingen, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Fröhlich
authors.forename: G
authors.initials: G
authors.lastname: Schaumburg-Lever
authors.forename: C
authors.initials: C
authors.lastname: Klessen
mesh_terms: D000951:Antigens, Neoplasm; D002401:Cathepsin B / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000737:chemistry* / Q000473:pathology; D058950:Melanoma-Specific Antigens; D016253:Microscopy, Immunoelectron; D009363:Neoplasm Proteins / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry* / Q000473:pathology
chemical_list: D000951:Antigens, Neoplasm; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D002401:Cathepsin B