A perspective on anti-EGFR therapies targeting triple-negative breast cancer

Triple-negative breast cancer (TNBC), which lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), accounts for about 15-20% of breast cancers and is the most aggressive breast cancer subtype. There are currently no effective therapies against metastatic TNBC. Compared with other breast cancer subtypes, EGFR is frequently overexpressed in TNBC and a potential therapeutic target for this disease. There are two types of EGFR inhibitors, small molecular tyrosine kinase inhibitor (TKI) and monoclonal antibody (mAb), for the treatment of cancers, such as non-small cell lung cancer and colorectal cancer. For breast cancer, however, the clinical trials of EGFR inhibitors have failed due to low response rates. Because a small portion of patients do demonstrate response to EGFR inhibitors, it may be necessary to stratify patients to enhance the efficacy of EGFR inhibitors in TNBC and to develop the effective combination therapy for this patient population. In this review, we describe some of the molecular mechanisms underlying EGFR inhibitor sensitivity and further discuss the possible therapeutic strategies to increase the efficacy of EGFR inhibitors in TNBC.