The goal of this study is to mechanistically define the potential anticancer activities of the osteoporosis bisphosphonate (BP) drug alendronate, and extend the analysis to learn novel information about the impact of BP on gamma delta (γδ) T cells in breast tissues as well as epithelial breast cell differentiation of high-risk women. To this end, we have designed a BP "window trial" to examine the effect of 1 - 3 weeks administration of alendronate on women at high-risk for breast cancer, at the level of immunosurveillance and mammary epithelial cell differentiation.