In the context of T2DM increasing the risk of lymph node metastasis, an in vitro study reported that T2DM promoted breast cancer metastasis through the resulted functional alterations of the human mesenchymal stem cells (MSCs)-derived exosomes associated with excess secretion of IL-6 from MSCs and the JAK/STAT3 pathway in breast cancer cells [162]. Here, STAT3 is linked to type 2 diabetes mellitus.