New personalized strategies for preventing and treating breast cancers are in need. In Sweden today, about 20 women receive the devastating news of a primary breast cancer diagnosis daily. Although an increasing number of targeted agents are now available for treatment, chemotherapy remains the backbone in many treatment regimens and is nowadays generously offered to patients with large  and aggressive primary tumors or cases with verified lymph node metastases in the preoperative setting to allow for the possibility of breast conservation surgery. The optimal goal of any treatment strategy is to improve survival while maintaining the quality of life and avoiding needless toxic effects of an ineffective treatment. To reach this safety goal, early assessment of therapeutic efficacy is critical. The current gold standard for assessing response and efficacy of preoperative (chemo)therapy is pathological complete response (pCR), which has the limitation that it is usually assessed only after completing several cycles of a often times toxic treatment. Remarkably, pCR is seldom achieved and is limited in predicting long-term prognosis in estrogen receptor positive breast cancer (constituting 70% of breast cancers), although a clinically relevant treatment benefit is still recorded in patients not achieving a pCR within this subgroup. Precise prognostic and treatment predictive biomarker are warranted. Our research aims to identify new treatment strategies and precise biomarkers for early assessment of treatment response and predicting prognosis. Further, we seek to provide a definitive characterisation of rare subsets of breast cancers such as the normal-like  and ER-low breast cancers by integrating tumor pathology, transcriptomic and immunohistochemical data with other clinical, genetic, and circulatory biomarkers. We focus on an interdisciplinary approach and rely on a team of researchers with outstanding knowledge of the study area and who share our vision for a truly personalized and durable breast cancer therapy in the near future.