CXCR4 and breast cancer: A study demonstrated that the type 2 diabetes mellitus (T2DM) can alter the phenotype of AT-MSC-exos, causing them to exhibit a greater induction of the upregulation of genes associated with BC cell migration (e.g., C-X-C receptor 4 (CXCR4) and vascular endothelial growth factor C (VEGF)-C) and genes associated with BC cell metastasis (e.g., transforming growth factor-beta (TGF-β), basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF)) [74].