Identification of stable markers of EGFR inhibitor resistance in breast cancer

EGFR expression in primary mammary tumors predicts for decrease patient surival, but targeted EGFR inhibitors have failed to improve patient outcomes. To identifiy mediators of resistance to EGFR inhibition in breast cancer, normal murine mammary gland (NMuMG) cells specifcally transformed by overexpression of EGFR (NME) were cultured under 3D conditions in the presence of the EGFR inhibitor AG1478. Using this approach we were able to isolate a cell conlony that demonstrated sponaneous resistance to inhibition of EGFR. These AG1478 resistant (AGR) cells were expanded in vitro and analysed by microarray. Each of the three groups were analyzed in triplicate, three control NME samples and three AGR samples.