Figure 2
Characterization of Her2 expression on breast cancer cell lines. We examined several breast cancer cell lines to identify cells that expressed Her2. The number of Her2-binding sites was determined by flow cytometry with anti-Her2 antibody conjugated to fluorescein. (a) Flow cytometric profiles, with cell number plotted as a function of fluorescence intensity, for three representative breast cancer cell lines are shown. (b) The number of Her2 sites per cell is calculated by comparison with a range of microspheres with known binding capacities. As expected, MCF7 breast cancer cells engineered to overexpress Her2-18 have a very high number of Her2-binding sites per cell (11.28 × 106), followed by BT-474 breast cancer cells (2.75 × 106), MCF7 breast cancer cells (0.18 × 106), and MDA-MB-231 breast cancer cells (0.11 × 106). The Chinese hamster ovary (non-breast) cell line has a very low number of Her2-binding sites per cell (< 4,000). Her2, human epidermal growth factor-like receptor 2.