Properties of epithelial cells cultured from human carcinomas and nonmalignant tissues.

Human epithelial cell cultures were examined for expression of plasminogen activator and fibronectin matrix. All of the cells examined showed ultrastructural evidence suggesting their epithelial origin, including microvilli and specialized junctions. The nonmalignant cells were also negative for endothelial cell markers (ie. they lacked factor VIII antigen, a nonthrombogenic surface and Weibel-Palade bodies). The nonmalignant lines all produced large amounts of plasminogen activator, whereas the tumor-derived lines showed a gradation of activities, ranging from lines having as much activity as the nonmalignant lines to lines having little or no activity above background. For both normal and malignant cells, addition of dexamethesone only slightly decreased the levels of plasminogen activator. By immunofluorescence microscopy, normal bladder and fetal intestine epithelial cells showed fibronectin in a globular and fibrillar matrix. In contrast, normal mammary epithelial cells had a much diminished amount of fibronectin with a punctate distribution.