Druggable molecular targets of triple-negative breast cancer and prospects of therapeutic application

Abstract

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, which is characterized by deficient expression of estrogen receptor, progesterone receptor expression and the absence of human epidermal growth factor receptor 2 (HER2) expression/amplification. For the past few decades, due to the lack of druggable targets, conventional chemotherapy has been the mainstay of systemic treatment for TNBC. However, lack of molecular targeted therapies and poor prognosis of TNBC, much research has been devoted to identifying specific molecular targets that can be utilized for targeted cancer therapy to improve the clinical outcomes. Now, poly (ADP-ribose) polymerase (PARP) inhibitors, immune checkpoint inhibitors, and antibody-drug conjugates have been approved by FDA for the treatment of TNBC. Moreover, agents that target signal transduction, angiogenesis, epigenetic modifications, and cell cycle are under active preclinical or clinical investigations. In this review, we summarize current significant achievements applied in treatment of TNBC with molecular targeted therapy, immunotherapy, and antibody-drug conjugates and upcoming drugs for triple negative breast cancer will be summarized. Key words: triple-negative breast cancer (TNBC), breast cancer, estrogen