1. Department of Gynecology and Obstetrics University Medical Center Regensburg Regensburg Germany
2. Institute of Pathology, Philipps‐University Marburg UKGM University Hospital Marburg Marburg Germany
3. Department of Gynecology and Obstetrics University Hospital Frankfurt Frankfurt Germany
4. Breast Cancer Center Charité Universitätsmedizin Berlin Berlin Germany
5. Department of Gynecology and Obstetrics Schleswig‐Holstein University Hospital Kiel Germany
6. Department of Medicine II, Hematology and Oncology Goethe University of Frankfurt Frankfurt Germany
7. Division of Stem Cells and Cancer, German Cancer Research Center (DKFZ) and DKFZ‐ZMBH Alliance Institute for Stem Cell Technology and Experimental Medicine (HI‐STEM gGmbH), German Cancer Consortium (DKTK) Heidelberg Germany
8. Department of Translational Research, Institute Curie PSL Research University Paris France
9. Institute of Pathology Technical University Munich Munich Germany
10. Division of Personalized Tumor Therapy Fraunhofer Institute for Toxicology and Experimental Medicine Regensburg Germany
11. Department of Experimental Medicine University of Regensburg Regensburg Germany
12. Institute of Pathology University of Regensburg
13. German Breast Group GBG Forschungs GmbH Neu‐Isenburg Germany