Figure 2: The cloned BCS cell-binding aptamer BCS/A35 recognized a BCS cell membrane surface protein that was distinguishable from ABCG2. A. BCS/ A35 cannot stain the differentiated breast cancer MCF-7 cells: left section, cells were stained with DAPI; middle section, with FITC-labeled BCS/A35; right section, merge of the previous two sections. B. BCS/A35 stained some of the mammosphere cells derived from MCF-7. C. BCS/A35 cannot stain the parental BHK cells. D. BCS/A35 cannot stain the ABCG2-expressing BHK/ ABCG2 cells.