MDSCs in breast cancer: metastasis, lipid metabolism, and therapeutics

Myeloid-derived suppressor cells (MDSCs) are one of the major contributors to the immunosuppressive microenvironment of breast cancer (BCa). MDSCs have unique mechanisms for each BCa metastasis site, and lipid metabolism acts as an energy source necessary to perform the role of MDSCs. In addition, MDSCs show different characteristics depending on BCa subtype. Currently, there is no clear understanding of MDSCs tailored to subtypes and metastatic sites in breast cancer. Here, we reviewed the biology and function of MDSCs revealed in BCa, focusing on metastasis and lipid metabolism, and discussed treatments targeting MDSCs. Understanding MDSC properties and function by BCa subtype and metastatic niche will be a prerequisite for taking the next step in subdividing BCa patients and providing customized treatment.