fig2

Figure 2. Epidermal growth factor pathway in triple negative breast cancers. EGFR is a tyrosine-kinase transmembrane receptor. When a ligand, mainly EGF, binds the extracellular domain, there is a dimerization of two receptors. This leads to their activation through phosphorylation of the intracellular tyrosine kinase. Cetuximab is a humanized anti-EGFR receptor, which competitively binds to the extracellular domain, blocking receptor dimerization. EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; TGFα: transforming growth factor-α; MAPK: mitogen-activated protein kinase; PIK3: phosphatidylinositol 3-kinase