Exosome-Derived microRNA: Implications in Melanoma Progression, Diagnosis and Treatment.

Melanoma is a malignant and aggressive cancer, and its progression is greatly affected by interactions between melanoma cells and their surroundings. Exploration on mechanism of melanoma and improved diagnostic and therapeutic strategies are becoming increasingly important. Unlike extracellular messengers that mainly work on targeted cells through corresponding receptors, exosomes are essential intercellular messengers that deliver biologically active substances such as nucleic acids and proteins to target cells for cell-cell communication. Of them, microRNAs (miRNAs) are common and important exosomal components that can regulate the expression of a wide range of target genes. Accordingly, exosome-derived miRNAs play a significant role in melanoma progression, including invasion and metastasis, microenvironment establishment, angiogenesis, and immune escape. MiRNA signatures of exosomes are specific in melanoma patients compared to healthy controls, thus circulating miRNAs, especially exosomal miRNAs, become potential diagnostic markers and therapeutic targets for melanoma. This review aims to summarize recent studies on the role of exosomal miRNAs in melanoma as well as ongoing efforts in melanoma treatment.