Figure 2. Schematic depicting resistance to EGFR and HER2 inhibitors due to activation of bypass track signaling.
Left) Model of a sensitive EGFR or HER2-addicted cancer treated with an ERBB small molecule inhibitor or antibody resulting in suppression of downstream signaling. EGFR or HER2 homodimers and heterodimers are shown. Right) Model of a EGFR mutant or HER2-amplified cancer with resistance due to maintenance of downstream signaling in the presence of the EGFR or HER2 inhibitors. Activation of signaling can be caused by activation of other RTKs or mutational activation of downstream signaling.