A monoclonal antibody which identifies an antigen in endothelial cell and epithelial basement membrane.

We isolated a monoclonal antibody which decorates the endothelial cells of normal and lymphatic vessels in formalin-fixed, paraffin-embedded tissue. In addition, the antibody recognizes a previously undescribed substance found in the basement membrane zone and subbasement membrane zone of a variety of epithelial. By ELISA assay, the antigen recognized by this monoclonal antibody is not laminin, type IV collagen or fibronectin. This antibody may be used as a diagnostic tool because it identifies an epitope in neoplasms differentiating towards endothelial cell such as angiosarcoma and Kaposi's sarcoma.