The pro-angiogenic effect of syndecan-1 was shown in myeloma (27), medulloblastoma (24), and in a variety of tumors of epithelial origin like endometrial cancer (38), breast cancer (39), and in stromal fibroblasts of breast cancer (32), but the effects of syndecan-1 in the angiogenesis of mesenchymal tumors is largely unknown. Here, SDC1 is linked to breast cancer.