Mesenchymal stem cell exosomes: a two-edged sword in cancer therapy

Mesenchymal stem cells (MSCs) are multipotent stromal cells present in various adult tissues. Several studies suggest that MSCs secrete exosomes that perform as mediators in the tumor niche and play several roles in tumorigenesis, angiogenesis, and metastasis. In contrast, there are other studies supporting the tumor-suppressing effects of MSC-derived exosomes. Therefore, the exact association of MSC exosomes and tumor cells remains open to debate. This review aimed to demonstrate the present knowledge of MSC-derived exosomes in cancer research and to illustrate current approaches to make use of modified exosomes as a platform in therapeutic strategies in cancer.