The HER-2 ECD is a blood test that can determine the extracellular domain (ECD) of the HER2 protein. It is believed (but not proven)that the HER2 ECD is shed into the blood circulation and can be elevated in patients with metastatic breast cancer. This blood test has been found to be useful in the follow-up and monitoring of patients with metastatic breast cancer. However the clinical utility of the serum HER2 ECD assay for predicting response to trastuzumab-based therapy has not been fully established. The serum HER-2 ECD assay has been reported upon at the 2002 San Antonio Breast Cancer Symposium and the 2003 Annual Meeting of the American Society of Clinical Oncologists (ASCO).

The address below should take you to several relevant articles (at www.docguide.com)that address preliminary clinic findings associated with use of the serum HER-2 ECD assay.