This project is an immunohistochemical study of archived patient breast tissue, specifically pre-invasive lesion specimens. The purpose is the discovery of novel molecular markers of pre-invasive breast lesions. These novel markers, once validated in this study, can serve as targets for individualized prevention therapy, neoadjuvant therapy for ductal carcinoma in situ (DCIS), or predictors of lesion aggressiveness. We have discovered two novel classes of DCIS molecular pathways required for the survival of DCIS neoplastic cells that will serve as the basis for the candidate molecules to be evaluated in this proposed study. The first class of DCIS molecular markers is autophagy, a cell survival mechanism that we discovered to be highly augmented in the hypoxic and nutrient deprived intraductal neoplastic cells of human DCIS (1-4). The second class of biomarker is calcium efflux that is mediated in breast cells by the calcium export pump Plasma Membrane Calcium ATPase (PMCA2) (5, 6). During normal lactation, breast epithelium pumps large concentrations of calcium into milk. In neoplastic lesions, calcium is exported by PMCA2 as a cell survival mechanism, since cells under metabolic stress accumulate calcium to a toxic level. Calcium export in DCIS may also contribute to intraductal calcifications, a hallmark of high grade DCIS and the most common marker of DCIS on mammography (7).