Anthracyclines, targeted therapies and GnRHR, triple therapies for triple negative breast cancer
Triple-negative breast cancer (TNBC) is defined by tumours lacking estrogen and progesterone receptors as well as lacking the epidermal growth factor receptor 2 (EGFR2). While receptor positive breast cancers have proven to be amenable to a variety of receptor targeted therapies such as Tamoxifen and Herceptin, chemotherapy is the only systemic therapy for TNBC. There are no specific treatment guidelines for TNBC although the tumours are considered to be chemosensitive and the anthracyclines doxorubicin and epirubicin figure prominently in treatment regimes. Treatment for TNBC is relatively ineffective when compared to receptor positive tumours and the combination of chemotherapy with agents targeting pathways such as apoptosis and DNA repair has not lead to significant improvements.
A greater understanding of the apoptotic and DNA repair pathways in TNBC treated with anthracyclines is necessary. Another potential target is the gonadotropin releasing hormone receptor, GnRHR. This is known to be expressed on at least half TNBC cases and may be a promising target in combination with anthracyclines and small molecule targeted therapies.