The other family member, ErbB-3, has six tyrosine phosphorylation sites and effectively binds to PI3K.42 The ligand TGF-α also binds to EGFRs, activates the PI3K signaling pathway and promotes tumor growth and metastasis in colorectal cancer cells.43 EGFR antibodies, such as cetuximab and panitumumab, inhibit PI3K/Akt signal transduction by competitively binding to EGFRs, thus inhibiting the occurrence and development of cancer.44 This evidence concerns the gene AKT1 and cancer.