A. Representative photomicrographs illustrating double immunofluorescence localization of ErbB1-3 and ErbB2-4 in MDA-MB-231 cells (for details see legend to Figure 10). Scale bar = 25 μm. B. Quantitative analysis of MDA-MB-231 cells showing colocalization of ErbB1-3 with ErbB2-4 (for details see legend to Figure 2). C. Quantitative analysis of cells showing ErbB1-3 and ErbB2-4 in distinct locations within the same cell. Data were analyzed as described in Figure 2.