RPPA quantification of EGFR knockdown. Two biological samples and four control samples were printed on nitrocellulose coated slides (four technical replicates per sample). Signal detection was performed using NIR-fluorescent dye labeled secondary antibodies. Position of siEGFR (green) and siALLSTAR (blue) transfected samples is indicated (A). Spots are false color images of fluorescent signals. None of the signals reached the saturation range of the scanning instrument (Odyssey, LI-COR). Target protein knockdown was determined by comparing EGFR signal intensity between siEGFR and siAllstar transfected samples. The linear regression was calculated from a dilution series of whole cell lysate from MDA-MB-231 cells (B).