EGFR and cancer: Therefore various cell lines from each cancer type were probed for HER3 expression, including the breast cancer cell lines SKBr3, MCF-7, BT474, HCC1954, and BT549, NSCLC cell lines H522 and H226R (a cell line previously developed to be resistant to the anti-EGFR monoclonal antibody cetuximab [31], [32]), HNSCC lines SCC6 and SCC1, and the CRC lines LoVo and CaCO2 (Figure 1A).