Figure 1
From: New targets for therapy in breast cancer: Small molecule tyrosine kinase inhibitors
The ErbB family of receptor tyrosine kinases. Known ligands are listed above each receptor. Human epidermal growth factor receptor (HER)2 has no known ligand. The kinase domain of HER3 is inactive. ErbB receptors can also be activated by nonconventional agonists, such as decorin and Cripto-1, which are not shown here. AR, amphiregulin; BTC, betacellulin; EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; EPR, epiregulin; HB-EGF, heparin-binding epidermal growth factor; NRG, neuregulin; TGF, transforming growth factor.