Tyrosineresidues in the intracellular area are phosphorylated at some point during protein dimerization [152].Adaptor proteins that might be attracted to phosphorylated residues trigger messenger pathways downstream, including the PI3K/Akt andMAPK pathways (Figure 2) [153, 154].Furthermore, Akt/mTORC1-mediated HIF-α stimulates VEGF secretion and enhancing angiogenesis [155].The number common cause of breast cancer is HER2 amplification. This evidence concerns the gene ERBB2 and breast cancer.