Eligible healthy women >= 40 years old at average risk for developing breast cancer will be offered participation in the study at the time they present for routine screening mammogram (MM) at the University of Maryland Breast Screening Center and Baltimore Washington Medical Center; includes women who present to the center as a referral for further diagnostic workup of recent screening diagnosis of breast cancer <= to 3 months with mammographic findings on screening MM with BIRADS 0-6<= 3 months.