ABSTRACT
Breast cancer is a heterogeneous disease consisting of several histological types and multiple molecular subtypes driven by genetic and epigenetic
Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St. Baltimore, MD 21201, 410-706-1615. aEmail: geade001@umaryland.edu bEmail: yyao@som.umaryland.edu cEmail: qzhou@som.umaryland.edu *Corresponding author
changes in gene expression (Buerger et al. 1999, Lakhani 1999, Simpson et al. 2005, Sotiriou and Pusztai 2009). Breast cancer is one of several hormonerelated cancers. Estrogen, an important risk factor for breast cancer, is associated with initiation and progression of disease (Yager and Davidson 2006). Despite being highly curable with early detection and intervention, breast cancer is currently the second leading cause of cancer deaths among women (Siegel et al. 2011). The majority of breast cancer mortality results from drug resistance, disease progression, and development of metastases (Steeg 2006). As such, there is signifi cant interest in identifying new molecular biomarkers and therapeutic targets that might prove to be clinically valuable for treatment or monitoring of disease. A newly discovered class of regulatory molecules, microRNAs (miRs), has been implicated in several diseases including cancer (Calin and Croce 2006a). Advances in understanding the molecular pathways underlying breast cancer have found that miRs play important roles in the development and progression of disease.
