To the best of our knowledge, we are the first to show the dependence of upregulated plasma NRP-1 levels in breast cancer patients with advanced lymph node metastasis when more than 10 axillary lymph nodes or other nodes (infraclavicular, supraclavicular or internal mammary nodes) are involved (N3 disease). This evidence concerns the gene NRP1 and metastatic malignant neoplasm in the lymph nodes.