Figure 2

Titration of cell lines for HER2 signal. To test the sensitivity of HER2 detection in blood, real time quantitative RT-PCR was performed on RNA isolated from mock positive controls of 8 ml of leukopak cells spiked with serial dilutions of breast cancer cell lines with varying levels of HER2 expression. The control samples were immunomagnetically selected with BerEP4 antibody prior to RNA isolation. Error bars represent the standard deviation of duplicate PCR reactions. If a sample never crossed the threshold, it is plotted as zero on this graph.