Prospective Validation Trial of Circulating Tumor Cells (CTCs) in Women With Metastatic Breast Cancer

Primary Objectives: 1. To validate the prognostic significance of circulating tumor cells (CTCs) in patients with newly diagnosed metastatic breast cancer (MBC). 2. To prospectively determine if assessment of CTCs can be used to stratify patients with MBC into two prognostic groups independent of existing methods i.e. hormone-receptor status, site of metastasis (e.g. visceral vs. non visceral) and treatment administered (e.g. chemotherapy vs. hormonal therapy). 3. To incorporate this information into the current TNM staging system by sub-classifying stage IV disease into two prognostic groups, Stage IVA and Stage IVB. Secondary Objective: 1\. To perform global gene profiling on selected specimens and correlate the profiles with clinical outcomes.