However, several studies have since demonstrated a key role of HER3 in the activation of the PI3K/AKT signalling pathway in EGFR, HER2, and the hepatocyte growth factor receptor, MET, addicted tumours, and in particular, resistance to HER inhibitors such as cetuximab [103,104,105,106,107]. The gene discussed is ERBB3; the disease is neoplasm.