Epidermal growth factor receptor mutations in breast Cancer: Therapeutic challenges and way forward.

Abstract

Epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase (RTK) that is upregulated in aggressive triple-negative breast cancer (TNBC). Ligands such as EGF, TGF-α, epigen, and amphiregulin activate the auto-phosphorylation activity of tyrosine residues on EGFR, which regulates the growth, proliferation, adhesion, migration, and survival of cancer cells. Our prior studies depicted that inhibition of EGFR modulates the chemosensitivity in breast cancer stem cells and, thus, serves as a potent therapeutic target in breast cancer. Small-molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) specifically targeting EGFR have been clinically approved for breast cancer treatment. However, intrinsic and acquired resistance generated due to EGFR mutations limits the applications of designed EGFR-TKIs in breast cancer patients. This review highlights the therapeutic approaches, and the challenges encountered in targeting EGFR-specific mutations. It suggests the need to develop more advanced higher-generation inhibitors for use in combinatorial therapy along with chemo-or-immune therapeutics in clinics as a breast cancer treatment strategy against relapse of the disease.