Comparative distribution of fibronectin and vitronectin in human breast and colon carcinomas. An immunofluorescence study.

Distribution of two extracellular matrix components, vitronectin and fibronectin, was studied by immunofluorescence in 40 breast infiltrating duct carcinomas and in 15 colonic adenocarcinomas. Blood vessels, especially in peritumoral colonic submucosa, gave markedly different images after staining by antivitronectin antibody and antifibronectin serum. The former exclusively decorated the elastic laminae, whereas the latter gave a reaction much closer to the endothelium, probably localized at the basement membrane of the endothelium. Strong labeling of colonic and mammary stroma carcinomas by polyclonal antiserum against fibronectin was observed, whereas monoclonal antibody against vitronectin gave much more restricted labeling in the stroma of these tumors. In the stroma of colonic carcinomas, vitronectin was often situated in areas in which elastic fibers were visualized by orcein counterstaining. In breast stroma carcinomas it was always localized only in elastosis areas. Thus, it is likely that antivitronectin binds with glycoprotein(s) associated with elastic fibers. However, vitronectin staining also was seen in areas in which no elastic fibers were characterized by the orcein method.