Lymphatic endothelium and Kaposi's sarcoma spindle cells detected by antibodies against the vascular endothelial growth factor receptor-3.

Lymphatic vessels have been difficult to study in detail in normal and tumor tissues because of the lack of molecular markers. Here, monoclonal antibodies against the extracellular domain of the vascular endothelial growth factor-C receptor that we have named VEGFR-3 were found to specifically stain endothelial cells of lymphatic vessels and vessels around tumors such as lymphoma and in situ breast carcinoma. Interestingly, the spindle cells of several cutaneous nodular AIDS-associated Kaposi's sarcomas and the endothelium around the nodules were also VEGFR-3 positive. The first specific molecular marker for the lymphatic endothelium should provide a useful tool for the analysis of lymphatic vessels in malignant tumors and their metastases and the cellular origin and differentiation of Kaposi's sarcomas.