**5. Conclusions**

Treatment with ADSC CM promoted the transmigration and invasion of MCF-10A cells and stimulated the expression of mesenchymal markers, suggesting EMT-like changes in mammary epithelial cells. Further, ADSC CM, in combination with irradiation, revealed increased mRNA levels of ECM markers in mammary epithelial cells and fibroblasts. We further observed the enhanced expression of tumor-promoting cytokines, which might play an important role in the presence of microscopic residual tumor foci after BCT. The data of the present study suggest a careful consideration of the need for lipotransfer after BCT of the individual patient.

**Author Contributions:** Conceptualization: T.P., A.K.-W.; methodology: T.P., A.K.-W., C.-S.K., T.J., S.K., R.S.; validation: C.-S.K., T.P., A.K.-W.; formal analysis: C.-S.K., T.P., A.K.-W., T.J.; investigation: C.-S.K., T.J.; data curation: C.-S.K.; writing—original draft preparation: T.P., A.K.-W.; writing—review and editing: C.-S.K., T.J., L.V.D., S.K., R.S., A.A., R.E.H.; visualization: T.P., C.-S.K.; supervision: T.P., A.K.-W., L.V.D., R.E.H., A.A.; project administration: A.K.-W., T.P.; funding acquisition: T.P., A.K.-W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Manfred Roth Foundation, the Forschungsstiftung Medizin University Hospital Erlangen, and ELAN FAU (grant number 18-12-19-1). We further want to acknowledge support by Boya Marshall. C.-S.K. was supported by the interdisciplinary center for clinical research (IZKF) at Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany. We acknowledge financial support by Deutsche Forschungsgemeinschaft and Friedrich-Alexander-Universität Erlangen-Nürnberg within the funding programme "Open Access Publication Funding".

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

**Acknowledgments:** We would like to thank Matthias Rübner, Department of Obstetrics and Gynaecology, for providing us with the MCF10A cell line and Stefan Fleischer and Ilse Arnold-Herberth for their excellent technical support. The present work was performed in (partial) fulfilment of the requirements for obtaining the degree "Dr. med." for Chiara-Sophia Kutz.

**Conflicts of Interest:** The authors declare no conflict of interest.
