From the Department of Medical Oncology, The Cancer Institute of New Jersey, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, New Brunswick, New Jersey
Authors' disclosures of potential conflicts of interest are found at the end of this article.
Address reprint requests to Antoinette R. Tan, MD, The Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901; e-mail: tanan{at}umdnj.edu
Overview: Basal-like breast cancer as defined by gene expression microarray analysis is characterized by low expression of estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) gene clusters and positive expression of cytokeratins 5/6 and epidermal growth factor receptor (EGFR). This subtype comprises 12% to 20% of all breast carcinomas. The majority lack expression of ER, progesterone receptor, and HER2, and this group is commonly referred to as "triple-negative" in the clinical setting. Although there is considerable overlap between basal-like breast cancer and breast cancer that is triple-negative, the terms are not synonymous, but are often used interchangeably. Basal-like and triple-negative breast cancers are a challenge to treat because there is no known target. There is no role for endocrine or HER2-directed therapy, but chemotherapy is effective. This article reviews the utility of DNA-damaging drugs and other compounds, specifically inhibitors of EGFR, poly(ADP-ribose) polymerase, angiogenesis, Src tyrosine kinase, and mammalian target of rapamycin, as well as others that are currently being tested in clinical trials specific to patients in these breast cancer subgroups.
