Breast cancer is a heterogeneous disease with a large variability in clinical outcome. Around two thirds of all breast cancer patients are cured by surgery as single treatment modality. Thus only one third need additional medical therapy, which today however, is delivered to 80-90% of the patients. Our selection criteria for low- and high-risk patients need consequently to be improved. The choice of adjuvant therapy should ideally be based on treatment predictive factors. So far, only a few factors are in clinical use; estrogen (ER) receptor for the choice of endocrine therapy, and the growth factor receptor (HER2) for anti-HER2 therapy. Generally accepted, clinically useful markers for predicting the sensitivity to chemo- and radiotherapy are still lacking. Finding molecular signatures for the identification of patients who could be spared chemotherapy is considered to have the highest priority among breast cancer specialists world-wide.
Using immunohistochemistry we are, in clinically well-defined materials, evaluating the importance of, for example: biomarkers involved in proliferation, the mTOR signaling pathway, ALDH1 (a stem cell marker), IGF1R, AIB1 (a co-factor for ER) and GPER1 (G-protein-coupled estrogen receptor) as well as apoptotic markers. Techniques within whole genome sequencing and gene profiling are also applied