Breast cancer is a leading cause of cancer mortality in women worldwide. According to estimates, approximately 46,000 women in the United States, and 130,000 women in the European Union, die due to breast cancer yearly. Early detection is of paramount importance in reducing mortality from this major public health burden. Screening mammography has been shown to reduce breast cancer mortality by 20% to 35% in women aged 40 to 69 years. Detection of small volume breast cancer at early stages is associated with a 10-year disease-free survival rate as high as 98% in patients with pT1a,bN0M0 tumors (measuring 1 cm or less, with disease-free axillary lymph nodes and no distant metastasis). The assumption that early diagnosis will lead to improved treatment outcomes has driven the search for diagnostic biomarkers.