Developing strategies to enhance cancer prevention is a paramount goal, particularly given recent concerns about surgical treatment of preinvasive states such as ductal carcinoma in situ. Promoting effective immunosurveillance by leukocytes that scan for nascent neoplastic transformations represents a potential means to achieve this goal. Because most breast cancers arise within the ductal epithelium, enhancing protective immunosurveillance will likely necessitate targeting one or more of the distinctive lymphocyte types found in these sites under normal conditions. Here, we have characterized the intraepithelial lymphocyte compartment of non-cancerous human breast tissue and identified a subset of T lymphocytes that can be pharmacologically targeted to enhance their responses to breast cancer cells. Specifically, Vδ2⁺ γδ T cells were consistently present in preparations of mammary ductal epithelial organoids and they proliferated in response to zoledronic acid, an aminobisphosphonate drug. Vδ2⁺ T cells from breast ductal organoids produced the antitumor cytokine IFNγ and efficiently killed bisphosphonate-pulsed breast carcinoma cells. These findings demonstrate the potential for exploiting the ability of Vδ2⁺ γδ T cells to respond to FDA-approved bisphosphonate drugs as a novel immunotherapeutic approach to inhibit the outgrowth of breast cancers. Cancer Prev Res; 9(4); 305–16. ©2016 AACR.