The FDA has approved Navidea Biopharmaceuticals' radioactive tracer Lymphoseek for breast cancer and melanoma intraoperative lymphatic mapping. The FDA said the tracer is the first agent for lymph node mapping to gain approval in more than three decades. "Removal and pathologic examination of lymph nodes draining a primary tumor is an important diagnostic evaluation for some patients with breast cancer or melanoma," said Dr. Shaw Chen of the FDA Center for Drug Evaluation and Research.