 - Find characteristics of different CTC populations: We hypothesize that CTCs will be enriched for cancer stem cell markers as well as markers for poor prognosis and aggressive tumor growth. Our novel approach to screen and quantify a panel of biomarkers simultaneously with analysis of the CTC markers utilized by the CellSearch system to analyze of CTCs is unique. We view our assays as potential liquid biopsies that can screen for markers of prognosis, sensitivity to chemotherapy, response to therapy, as well as for proteins involved in proliferation, apoptosis, and immune response. 