Circulating MicroRNAs in Cutaneous Melanoma Diagnosis and Prognosis

Cutaneous melanoma represents a challenge for pharmacologists and clinicians due to their high degree of genetic and phenotypic heterogeneity. The identification of new non-invasive and informative biomarkers would therefore represent a substantial step to adequately treat melanoma patients. MicroRNAs (miRNAs) are a class of small non-coding RNAs that play an important role as negative regulators of gene expression. Several studies have demonstrated their correlation with disease status in different types of cancer including melanoma. Extracellular miRNAs are released from both tumor cells and/or normal cells. MiRNAs do not circulate freely in biological fluids but they are incorporated into extracellular vesicles or form complexes with lipids and proteins. Circulating miRNAs may represent potential biomarkers of cutaneous melanoma diagnosis and patient prognosis. Longitudinal monitoring of cell-free miRNAs in biological fluids of melanoma patients could help clinicians to predict disease progression before the tumor becomes resistant to a given drug. However, to confirm their clinical utility it will be necessary to validate the best available technique for their detection and quantification and to test selected miRNAs in prospective clinical trials.