ERBB2 and cancer: Human growth receptor bound protein 7 (Grb7) is a 532 amino acid long adapter protein implicated in cancer progression and invasion upon interaction with its binding partners comprising various receptor tyrosine kinases (RTKs) such as epidermal growth factor receptor (ErbB2/HER2) [214], ErbB3 and ErbB4 [215], focal adhesion kinase (FAK) [216], and platelet-derived growth factor (PDGF) receptors [217].