Figure 5. A proteomics‐based approach to the development of new breast cancer companion diagnostics, for predicting Tamoxifen‐resistance. For this analysis, data from the proteomics analysis of MCF7‐ fibroblast co‐cultures was intersected with clinical outcome data. More specifically, the clinical population we focused included ER(+) patients, of the luminal A sub‐type, that were lymph‐node positive (LN(+)) at diagnosis, who were treated with Tamoxifen and followed over nearly 200 months. In this context, we ultimately evaluated the prognostic value of a mitochondrial signature for predicting tumor treatment failure (recurrence, metastasis or overall survival).