EGFR and cancer: Cancer cell-specific uptake of PEGylated nanoparticles mediated by PEG engagers was examined by real-time confocal microscopy cell imaging of EGFR-negative MCF7 cells or EGFR-positive MDA-MB-468 and A431 cells treated stepwise with PEG engagerEGFR or PEG engagerCD19 and then fluorescent PEGylated Qtracker 655 non-targeted quantum dots (PEG-Qdot655).