Methods and systems are provided for the noninvasive measurement of the subepithelial impedance of the breast and for assessing the risk that a substantially asymptomatic female patient will develop or be at substantially increased risk of developing proliferative or pre-cancerous changes in the breast, or may be at subsequent risk for the development of pre-cancerous or cancerous changes. A plurality of electrodes are used to measure subepithelial impedance of parenchymal breast tissue of a patient at one or more locations and at least one frequency, particularly moderately high frequencies. The risk of developing breast cancer is assessed according to measured and expected or estimated values of subepithelial impedance for the patient and according to one or more experienced-based algorithms. Devices for practicing the disclosed methods are also provided.